tview/lib/backends/tex_inspect_opengl.cpp

709 lines
33 KiB
C++

// ImGuiTexInspect, a texture inspector widget for dear imgui
#if defined(_MSC_VER) && !defined(_CRT_SECURE_NO_WARNINGS)
#define _CRT_SECURE_NO_WARNINGS
#endif
#if defined EMSCRIPTEN && defined IMGUI_TEX_INSPECT_FLOAT_READ_ENABLED
#warning "Float texture read back is disabled on Emscripten"
#undef IMGUI_TEX_INSPECT_FLOAT_READ_ENABLED
#endif
#include "../imgui_tex_inspect_internal.h"
// ==========================================================================
// This file is largely based on:
// https://github.com/ocornut/imgui/blob/master/backends/imgui_impl_opengl3.cpp
//
// In the following section the ImGui_ImplOpenGL3_Init function has been
// changed to not rewrite global ImGui state. It has also been wrapped in a
// namespace to not clash with the main ImGui version. Aside from that this
// section is identical to the imgui original.
//
// It's reproduced here because none of this code is exposed in the ImGui API
// in a way that be reused (nor should it be).
//
// Search for "END COPIED" to find the end of the copied segment.
// ===========================================================================
// COPIED FROM imgui_impl_opengl3.cp ////////////////////////////////////////
#if defined(_MSC_VER) && !defined(_CRT_SECURE_NO_WARNINGS)
#define _CRT_SECURE_NO_WARNINGS
#endif
#include "../imgui.h"
#include "imgui_impl_opengl3.h"
#include <stdio.h>
#if defined(_MSC_VER) && _MSC_VER <= 1500 // MSVC 2008 or earlier
#include <stddef.h> // intptr_t
#else
#include <stdint.h> // intptr_t
#endif
// GL includes
#if defined(IMGUI_IMPL_OPENGL_ES2)
#include <GLES2/gl2.h>
#elif defined(IMGUI_IMPL_OPENGL_ES3)
#if (defined(__APPLE__) && (TARGET_OS_IOS || TARGET_OS_TV))
#include <OpenGLES/ES3/gl.h> // Use GL ES 3
#else
#include <GLES3/gl3.h> // Use GL ES 3
#endif
#else
// About Desktop OpenGL function loaders:
// Modern desktop OpenGL doesn't have a standard portable header file to load OpenGL function pointers.
// Helper libraries are often used for this purpose! Here we are supporting a few common ones (gl3w, glew, glad).
// You may use another loader/header of your choice (glext, glLoadGen, etc.), or chose to manually implement your own.
#if defined(IMGUI_IMPL_OPENGL_LOADER_GL3W)
#include <GL/gl3w.h> // Needs to be initialized with gl3wInit() in user's code
#elif defined(IMGUI_IMPL_OPENGL_LOADER_GLEW)
#include <GL/glew.h> // Needs to be initialized with glewInit() in user's code.
#elif defined(IMGUI_IMPL_OPENGL_LOADER_GLAD)
#include <glad/glad.h> // Needs to be initialized with gladLoadGL() in user's code.
#elif defined(IMGUI_IMPL_OPENGL_LOADER_GLAD2)
#include <glad/gl.h> // Needs to be initialized with gladLoadGL(...) or gladLoaderLoadGL() in user's code.
#elif defined(IMGUI_IMPL_OPENGL_LOADER_GLBINDING2)
#ifndef GLFW_INCLUDE_NONE
#define GLFW_INCLUDE_NONE // GLFW including OpenGL headers causes ambiguity or multiple definition errors.
#endif
#include <glbinding/Binding.h> // Needs to be initialized with glbinding::Binding::initialize() in user's code.
#include <glbinding/gl/gl.h>
using namespace gl;
#elif defined(IMGUI_IMPL_OPENGL_LOADER_GLBINDING3)
#ifndef GLFW_INCLUDE_NONE
#define GLFW_INCLUDE_NONE // GLFW including OpenGL headers causes ambiguity or multiple definition errors.
#endif
#include <glbinding/glbinding.h>// Needs to be initialized with glbinding::initialize() in user's code.
#include <glbinding/gl/gl.h>
using namespace gl;
#elif defined(IMGUI_IMPL_OPENGL_LOADER_EPOXY)
#include <epoxy/gl.h>
#else
#include <SDL2/SDL_opengl.h>
#include <SDL2/SDL_opengles2.h>
#include <SDL2/SDL_opengles2_gl2.h>
#endif
#endif
// Desktop GL 3.2+ has glDrawElementsBaseVertex() which GL ES and WebGL don't have.
#if !defined(IMGUI_IMPL_OPENGL_ES2) && !defined(IMGUI_IMPL_OPENGL_ES3) && defined(GL_VERSION_3_2)
#define IMGUI_IMPL_OPENGL_MAY_HAVE_VTX_OFFSET
#endif
// Desktop GL 3.3+ has glBindSampler()
#if !defined(IMGUI_IMPL_OPENGL_ES2) && !defined(IMGUI_IMPL_OPENGL_ES3) && defined(GL_VERSION_3_3)
#define IMGUI_IMPL_OPENGL_MAY_HAVE_BIND_SAMPLER
#endif
// Desktop GL 3.1+ has GL_PRIMITIVE_RESTART state
#if !defined(IMGUI_IMPL_OPENGL_ES2) && !defined(IMGUI_IMPL_OPENGL_ES3) && defined(GL_VERSION_3_1)
#define IMGUI_IMPL_OPENGL_MAY_HAVE_PRIMITIVE_RESTART
#endif
namespace imgui_impl_opengl
{
// OpenGL Data
static GLuint g_GlVersion = 0; // Extracted at runtime using GL_MAJOR_VERSION, GL_MINOR_VERSION queries (e.g. 320 for GL 3.2)
static char g_GlslVersionString[32] = ""; // Specified by user or detected based on compile time GL settings.
static GLuint g_ShaderHandle = 0, g_VertHandle = 0, g_FragHandle = 0;
static GLint g_AttribLocationTex = 0, g_AttribLocationProjMtx = 0; // Uniforms location
static GLuint g_AttribLocationVtxPos = 0, g_AttribLocationVtxUV = 0; // Vertex attributes location
static GLint g_UniformLocationForceNearestSampling = 0;
static GLint g_UniformLocationGridWidth = 0;
// Functions
static bool ImGui_ImplOpenGL3_Init(const char* glsl_version)
{
// Query for GL version (e.g. 320 for GL 3.2)
#if !defined(IMGUI_IMPL_OPENGL_ES2)
GLint major = 0;
GLint minor = 0;
glGetIntegerv(GL_MAJOR_VERSION, &major);
glGetIntegerv(GL_MINOR_VERSION, &minor);
if (major == 0 && minor == 0)
{
// Query GL_VERSION in desktop GL 2.x, the string will start with "<major>.<minor>"
const char* gl_version = (const char*)glGetString(GL_VERSION);
sscanf(gl_version, "%d.%d", &major, &minor);
}
g_GlVersion = (GLuint)(major * 100 + minor * 10);
#else
g_GlVersion = 200; // GLES 2
#endif
// Store GLSL version string so we can refer to it later in case we recreate shaders.
// Note: GLSL version is NOT the same as GL version. Leave this to NULL if unsure.
#if defined(IMGUI_IMPL_OPENGL_ES2)
if (glsl_version == NULL)
glsl_version = "#version 100";
#elif defined(IMGUI_IMPL_OPENGL_ES3)
if (glsl_version == NULL)
glsl_version = "#version 300 es";
#elif defined(__APPLE__)
if (glsl_version == NULL)
glsl_version = "#version 150";
#else
if (glsl_version == NULL)
glsl_version = "#version 130";
#endif
IM_ASSERT((int)strlen(glsl_version) + 2 < IM_ARRAYSIZE(g_GlslVersionString));
strcpy(g_GlslVersionString, glsl_version);
strcat(g_GlslVersionString, "\n");
// Debugging construct to make it easily visible in the IDE and debugger which GL loader has been selected.
// The code actually never uses the 'gl_loader' variable! It is only here so you can read it!
// If auto-detection fails or doesn't select the same GL loader file as used by your application,
// you are likely to get a crash below.
// You can explicitly select a loader by using '#define IMGUI_IMPL_OPENGL_LOADER_XXX' in imconfig.h or compiler command-line.
const char* gl_loader = "Unknown";
IM_UNUSED(gl_loader);
#if defined(IMGUI_IMPL_OPENGL_LOADER_GL3W)
gl_loader = "GL3W";
#elif defined(IMGUI_IMPL_OPENGL_LOADER_GLEW)
gl_loader = "GLEW";
#elif defined(IMGUI_IMPL_OPENGL_LOADER_GLAD)
gl_loader = "GLAD";
#elif defined(IMGUI_IMPL_OPENGL_LOADER_GLAD2)
gl_loader = "GLAD2";
#elif defined(IMGUI_IMPL_OPENGL_LOADER_GLBINDING2)
gl_loader = "glbinding2";
#elif defined(IMGUI_IMPL_OPENGL_LOADER_GLBINDING3)
gl_loader = "glbinding3";
#elif defined(IMGUI_IMPL_OPENGL_LOADER_CUSTOM)
gl_loader = "custom";
#else
gl_loader = "none";
#endif
// Make an arbitrary GL call (we don't actually need the result)
// IF YOU GET A CRASH HERE: it probably means that you haven't initialized the OpenGL function loader used by this code.
// Desktop OpenGL 3/4 need a function loader. See the IMGUI_IMPL_OPENGL_LOADER_xxx explanation above.
GLint current_texture;
glGetIntegerv(GL_TEXTURE_BINDING_2D, &current_texture);
return true;
}
// ===========================================================================
// COPIED FROM A DIFFERENT PART OF imgui_impl_opengl3.cpp
// ===========================================================================
// If you get an error please report on github. You may try different GL context version or GLSL version. See GL<>GLSL version table at the top of this file.
static bool CheckShader(GLuint handle, const char* desc)
{
GLint status = 0, log_length = 0;
glGetShaderiv(handle, GL_COMPILE_STATUS, &status);
glGetShaderiv(handle, GL_INFO_LOG_LENGTH, &log_length);
if ((GLboolean)status == GL_FALSE)
fprintf(stderr, "ERROR: ImGui_ImplOpenGL3_CreateDeviceObjects: failed to compile %s!\n", desc);
if (log_length > 1)
{
ImVector<char> buf;
buf.resize((int)(log_length + 1));
glGetShaderInfoLog(handle, log_length, NULL, (GLchar*)buf.begin());
fprintf(stderr, "%s\n", buf.begin());
}
return (GLboolean)status == GL_TRUE;
}
// If you get an error please report on GitHub. You may try different GL context version or GLSL version.
static bool CheckProgram(GLuint handle, const char* desc)
{
GLint status = 0, log_length = 0;
glGetProgramiv(handle, GL_LINK_STATUS, &status);
glGetProgramiv(handle, GL_INFO_LOG_LENGTH, &log_length);
if ((GLboolean)status == GL_FALSE)
fprintf(stderr, "ERROR: ImGui_ImplOpenGL3_CreateDeviceObjects: failed to link %s! (with GLSL '%s')\n", desc, g_GlslVersionString);
if (log_length > 1)
{
ImVector<char> buf;
buf.resize((int)(log_length + 1));
glGetProgramInfoLog(handle, log_length, NULL, (GLchar*)buf.begin());
fprintf(stderr, "%s\n", buf.begin());
}
return (GLboolean)status == GL_TRUE;
}
static void ImGui_ImplOpenGL3_SetupRenderState(ImDrawData* draw_data, int fb_width, int fb_height)
{
// Setup render state: alpha-blending enabled, no face culling, no depth testing, scissor enabled, polygon fill
glEnable(GL_BLEND);
glBlendEquation(GL_FUNC_ADD);
glBlendFuncSeparate(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA, GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
glDisable(GL_CULL_FACE);
glDisable(GL_DEPTH_TEST);
glDisable(GL_STENCIL_TEST);
glEnable(GL_SCISSOR_TEST);
#ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_PRIMITIVE_RESTART
if (g_GlVersion >= 310)
glDisable(GL_PRIMITIVE_RESTART);
#endif
#ifdef GL_POLYGON_MODE
glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
#endif
// Support for GL 4.5 rarely used glClipControl(GL_UPPER_LEFT)
#if defined(GL_CLIP_ORIGIN)
bool clip_origin_lower_left = true;
if (g_GlVersion >= 450)
{
GLenum current_clip_origin = 0; glGetIntegerv(GL_CLIP_ORIGIN, (GLint*)&current_clip_origin);
if (current_clip_origin == GL_UPPER_LEFT)
clip_origin_lower_left = false;
}
#endif
// Setup viewport, orthographic projection matrix
// Our visible imgui space lies from draw_data->DisplayPos (top left) to draw_data->DisplayPos+data_data->DisplaySize (bottom right). DisplayPos is (0,0) for single viewport apps.
glViewport(0, 0, (GLsizei)fb_width, (GLsizei)fb_height);
float L = draw_data->DisplayPos.x;
float R = draw_data->DisplayPos.x + draw_data->DisplaySize.x;
float T = draw_data->DisplayPos.y;
float B = draw_data->DisplayPos.y + draw_data->DisplaySize.y;
#if defined(GL_CLIP_ORIGIN)
if (!clip_origin_lower_left) { float tmp = T; T = B; B = tmp; } // Swap top and bottom if origin is upper left
#endif
const float ortho_projection[4][4] =
{
{ 2.0f/(R-L), 0.0f, 0.0f, 0.0f },
{ 0.0f, 2.0f/(T-B), 0.0f, 0.0f },
{ 0.0f, 0.0f, -1.0f, 0.0f },
{ (R+L)/(L-R), (T+B)/(B-T), 0.0f, 1.0f },
};
glUseProgram(g_ShaderHandle);
glUniform1i(g_AttribLocationTex, 0);
glUniformMatrix4fv(g_AttribLocationProjMtx, 1, GL_FALSE, &ortho_projection[0][0]);
glEnableVertexAttribArray(g_AttribLocationVtxPos);
glEnableVertexAttribArray(g_AttribLocationVtxUV);
//glEnableVertexAttribArray(g_AttribLocationVtxColor); //Our shader doesn't use vertex color
glVertexAttribPointer(g_AttribLocationVtxPos, 2, GL_FLOAT, GL_FALSE, sizeof(ImDrawVert), (GLvoid*)IM_OFFSETOF(ImDrawVert, pos));
glVertexAttribPointer(g_AttribLocationVtxUV, 2, GL_FLOAT, GL_FALSE, sizeof(ImDrawVert), (GLvoid*)IM_OFFSETOF(ImDrawVert, uv));
//glVertexAttribPointer(g_AttribLocationVtxColor, 4, GL_UNSIGNED_BYTE, GL_TRUE, sizeof(ImDrawVert), (GLvoid*)IM_OFFSETOF(ImDrawVert, col));
}
// ===========================================================================
// END COPIED FROM imgui_impl_opengl3.cpp
// ---------------------------------------------------------------------------
// Note that a lot of the following code still orginated in
// imgui_impl_opengl3.cpp but there are more changes from here on.
// ===========================================================================
// New uniforms for ImGuiTexInspect fragment shader
static GLint g_UniformLocationTextureSize;
static GLint g_UniformLocationColorTransform;
static GLint g_UniformLocationColorOffset;
static GLint g_UniformLocationBackgroundColor;
static GLint g_UniformLocationPremultiplyAlpha;
static GLint g_UniformLocationDisableFinalAlpha;
static GLint g_UniformLocationGrid;
// Vertex shaders are directly from imgui_impl_opengl3.cpp
const GLchar* vertex_shader_glsl_120 =
"uniform mat4 ProjMtx;\n"
"attribute vec2 Position;\n"
"attribute vec2 UV;\n"
"attribute vec4 Color;\n"
"varying vec2 Frag_UV;\n"
"varying vec4 Frag_Color;\n"
"void main()\n"
"{\n"
" Frag_UV = UV;\n"
" Frag_Color = Color;\n"
" gl_Position = ProjMtx * vec4(Position.xy,0,1);\n"
"}\n";
const GLchar* vertex_shader_glsl_130 =
"uniform mat4 ProjMtx;\n"
"in vec2 Position;\n"
"in vec2 UV;\n"
"in vec4 Color;\n"
"out vec2 Frag_UV;\n"
"out vec4 Frag_Color;\n"
"void main()\n"
"{\n"
" Frag_UV = UV;\n"
" Frag_Color = Color;\n"
" gl_Position = ProjMtx * vec4(Position.xy,0,1);\n"
"}\n";
const GLchar* vertex_shader_glsl_300_es =
"precision mediump float;\n"
"layout (location = 0) in vec2 Position;\n"
"layout (location = 1) in vec2 UV;\n"
"layout (location = 2) in vec4 Color;\n"
"uniform mat4 ProjMtx;\n"
"out vec2 Frag_UV;\n"
"out vec4 Frag_Color;\n"
"void main()\n"
"{\n"
" Frag_UV = UV;\n"
" Frag_Color = Color;\n"
" gl_Position = ProjMtx * vec4(Position.xy,0,1);\n"
"}\n";
const GLchar* vertex_shader_glsl_410_core =
"layout (location = 0) in vec2 Position;\n"
"layout (location = 1) in vec2 UV;\n"
"layout (location = 2) in vec4 Color;\n"
"uniform mat4 ProjMtx;\n"
"out vec2 Frag_UV;\n"
"out vec4 Frag_Color;\n"
"void main()\n"
"{\n"
" Frag_UV = UV;\n"
" Frag_Color = Color;\n"
" gl_Position = ProjMtx * vec4(Position.xy,0,1);\n"
"}\n";
//-------------------------------------------------------------------------
// [SECTION] IMGUI_TEX_INSPECT FRAGMENT SHADERS
//-------------------------------------------------------------------------
const GLchar *fragment_shader_glsl_120 = "#ifdef GL_ES\n"
" precision mediump float;\n"
"#endif\n"
"uniform sampler2D Texture;\n"
"uniform vec2 TextureSize;\n"
"uniform mat4 ColorTransform;\n"
"uniform vec4 ColorOffset;\n"
"uniform vec3 BackgroundColor;\n"
"uniform float PremultiplyAlpha;\n"
"uniform float DisableFinalAlpha;\n"
"uniform bool ForceNearestSampling;\n"
"uniform vec4 Grid;\n"
"uniform vec2 GridWidth;\n"
"varying vec2 Frag_UV;\n"
"void main()\n"
"{\n"
" vec2 uv;\n"
" vec2 texel = Frag_UV * TextureSize;\n"
" if (ForceNearestSampling)\n"
" uv = (floor(texel) + vec2(0.5,0.5)) / TextureSize;\n"
" else\n"
" uv = Frag_UV;\n"
" vec2 texelEdge = step(mod(texel,vec2(1.0,1.0)),GridWidth);\n"
" float isGrid = max(texelEdge.x, texelEdge.y);\n"
" vec4 ct = ColorTransform * texture2D(Texture, uv) + ColorOffset;\n"
" ct.rgb = ct.rgb * mix(1.0, ct.a, PremultiplyAlpha);\n"
" ct.rgb += BackgroundColor * (1.0-ct.a);\n"
" ct.a = mix(ct.a, 1.0, DisableFinalAlpha);\n"
" ct = mix(ct, vec4(Grid.rgb,1), Grid.a * isGrid);\n"
" gl_FragColor = ct;\n"
"}\n";
const GLchar *fragment_shader_glsl_130 = "uniform sampler2D Texture;\n"
"uniform vec2 TextureSize;\n"
"uniform mat4 ColorTransform;\n"
"uniform vec4 ColorOffset;\n"
"uniform vec3 BackgroundColor;\n"
"uniform float PremultiplyAlpha;\n"
"uniform float DisableFinalAlpha;\n"
"uniform bool ForceNearestSampling;\n"
"uniform vec4 Grid;\n"
"uniform vec2 GridWidth;\n"
"in vec2 Frag_UV;\n"
"out vec4 Out_Color;\n"
"void main()\n"
"{\n"
" vec2 uv;\n"
" vec2 texel = Frag_UV * TextureSize;\n"
" if (ForceNearestSampling)\n"
" uv = (floor(texel) + vec2(0.5,0.5)) / TextureSize;\n"
" else\n"
" uv = Frag_UV;\n"
" vec2 texelEdge = step(mod(texel,vec2(1.0,1.0)),GridWidth);\n"
" float isGrid = max(texelEdge.x, texelEdge.y);\n"
" vec4 ct = ColorTransform * texture(Texture, uv) + ColorOffset;\n"
" ct.rgb = ct.rgb * mix(1.0, ct.a, PremultiplyAlpha);\n"
" ct.rgb += BackgroundColor * (1.0-ct.a);\n"
" ct.a = mix(ct.a, 1.0, DisableFinalAlpha);\n"
" ct = mix(ct, vec4(Grid.rgb,1), Grid.a * isGrid);\n"
" Out_Color = ct;\n"
"}\n";
const GLchar *fragment_shader_glsl_300_es = "precision mediump float;\n"
"uniform sampler2D Texture;\n"
"uniform vec2 TextureSize;\n"
"uniform mat4 ColorTransform;\n"
"uniform vec4 ColorOffset;\n"
"uniform vec3 BackgroundColor;\n"
"uniform float PremultiplyAlpha;\n"
"uniform float DisableFinalAlpha;\n"
"uniform bool ForceNearestSampling;\n"
"uniform vec4 Grid;\n"
"uniform vec2 GridWidth;\n"
"in vec2 Frag_UV;\n"
"layout (location = 0) out vec4 Out_Color;\n"
"void main()\n"
"{\n"
" vec2 uv;\n"
" vec2 texel = Frag_UV * TextureSize;\n"
" if (ForceNearestSampling)\n"
" uv = (floor(texel) + vec2(0.5,0.5)) / TextureSize;\n"
" else\n"
" uv = Frag_UV;\n"
" vec2 texelEdge = step(mod(texel,vec2(1.0,1.0)),GridWidth);\n"
" float isGrid = max(texelEdge.x, texelEdge.y);\n"
" vec4 ct = ColorTransform * texture(Texture, uv) + ColorOffset;\n"
" ct.rgb = ct.rgb * mix(1.0, ct.a, PremultiplyAlpha);\n"
" ct.rgb += BackgroundColor * (1.0-ct.a);\n"
" ct.a = mix(ct.a, 1.0, DisableFinalAlpha);\n"
" ct = mix(ct, vec4(Grid.rgb,1), Grid.a * isGrid);\n"
" Out_Color = ct;\n"
"}\n";
const GLchar *fragment_shader_glsl_410_core = "uniform sampler2D Texture;\n"
"uniform vec2 TextureSize;\n"
"uniform mat4 ColorTransform;\n"
"uniform vec4 ColorOffset;\n"
"uniform vec3 BackgroundColor;\n"
"uniform float PremultiplyAlpha;\n"
"uniform float DisableFinalAlpha;\n"
"uniform bool ForceNearestSampling;\n"
"uniform vec4 Grid;\n"
"uniform vec2 GridWidth;\n"
"in vec2 Frag_UV;\n"
"layout (location = 0) out vec4 Out_Color;\n"
"void main()\n"
"{\n"
" vec2 uv;\n"
" vec2 texel = Frag_UV * TextureSize;\n"
" if (ForceNearestSampling)\n"
" uv = (floor(texel) + vec2(0.5,0.5)) / TextureSize;\n"
" else\n"
" uv = Frag_UV;\n"
" vec2 texelEdge = step(mod(texel,vec2(1.0,1.0)),GridWidth);\n"
" float isGrid = max(texelEdge.x, texelEdge.y);\n"
" vec4 ct = ColorTransform * texture(Texture, uv) + ColorOffset;\n"
" ct.rgb = ct.rgb * mix(1.0, ct.a, PremultiplyAlpha);\n"
" ct.rgb += BackgroundColor * (1.0-ct.a);\n"
" ct.a = mix(ct.a, 1.0, DisableFinalAlpha);\n"
" ct = mix(ct, vec4(Grid.rgb,1), Grid.a * isGrid);\n"
" Out_Color = ct;\n"
"}\n";
/* BuildShader is from imgui_impl_opengl3.cpp. Only change is to query the
* additional uniform locations for the new fragment shader*/
void BuildShader()
{
// Shader selection code based on imgui_impl_opengl3.cpp
// Parse GLSL version string
int glsl_version = 130;
sscanf(g_GlslVersionString, "#version %d", &glsl_version);
// Select shaders matching our GLSL versions
const GLchar *vertex_shader = NULL;
const GLchar *fragment_shader = NULL;
if (glsl_version < 130)
{
vertex_shader = vertex_shader_glsl_120;
fragment_shader = fragment_shader_glsl_120;
}
else if (glsl_version >= 410)
{
vertex_shader = vertex_shader_glsl_410_core;
fragment_shader = fragment_shader_glsl_410_core;
}
else if (glsl_version == 300)
{
vertex_shader = vertex_shader_glsl_300_es;
fragment_shader = fragment_shader_glsl_300_es;
}
else
{
vertex_shader = vertex_shader_glsl_130;
fragment_shader = fragment_shader_glsl_130;
}
if (fragment_shader == NULL)
{
fprintf(stderr, "ERROR: imgui_tex_inspect fragment shader for %s not implemented yet", g_GlslVersionString);
}
else
{
// Create shaders
const GLchar *vertex_shader_with_version[2] = {g_GlslVersionString, vertex_shader};
g_VertHandle = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(g_VertHandle, 2, vertex_shader_with_version, NULL);
glCompileShader(g_VertHandle);
CheckShader(g_VertHandle, "vertex shader");
const GLchar *fragment_shader_with_version[2] = {g_GlslVersionString, fragment_shader};
g_FragHandle = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(g_FragHandle, 2, fragment_shader_with_version, NULL);
glCompileShader(g_FragHandle);
CheckShader(g_FragHandle, "fragment shader");
g_ShaderHandle = glCreateProgram();
glAttachShader(g_ShaderHandle, g_VertHandle);
glAttachShader(g_ShaderHandle, g_FragHandle);
glLinkProgram(g_ShaderHandle);
CheckProgram(g_ShaderHandle, "shader program");
g_AttribLocationTex = glGetUniformLocation(g_ShaderHandle, "Texture");
g_AttribLocationProjMtx = glGetUniformLocation(g_ShaderHandle, "ProjMtx");
g_AttribLocationVtxPos = (GLuint)glGetAttribLocation(g_ShaderHandle, "Position");
g_AttribLocationVtxUV = (GLuint)glGetAttribLocation(g_ShaderHandle, "UV");
// Change from imgui_impl_opengl3.cpp (Our shader doesn't use vertex color)
//g_AttribLocationVtxColor = (GLuint)glGetAttribLocation(g_ShaderHandle, "Color");
// New uniforms used by imgui_tex_inspect
g_UniformLocationTextureSize = glGetUniformLocation(g_ShaderHandle, "TextureSize");
g_UniformLocationColorTransform = glGetUniformLocation(g_ShaderHandle, "ColorTransform");
g_UniformLocationColorOffset = glGetUniformLocation(g_ShaderHandle, "ColorOffset");
g_UniformLocationBackgroundColor = glGetUniformLocation(g_ShaderHandle, "BackgroundColor");
g_UniformLocationPremultiplyAlpha = glGetUniformLocation(g_ShaderHandle, "PremultiplyAlpha");
g_UniformLocationDisableFinalAlpha = glGetUniformLocation(g_ShaderHandle, "DisableFinalAlpha");
g_UniformLocationGrid = glGetUniformLocation(g_ShaderHandle, "Grid");
g_UniformLocationForceNearestSampling = glGetUniformLocation(g_ShaderHandle, "ForceNearestSampling");
g_UniformLocationGridWidth = glGetUniformLocation(g_ShaderHandle, "GridWidth");
}
}
} // namespace imgui_impl_opengl
namespace ImGuiTexInspect
{
using namespace imgui_impl_opengl;
static GLuint readbackFramebuffer = 0;
//-------------------------------------------------------------------------
// [SECTION] Init and Shutdown
//-------------------------------------------------------------------------
bool ImplOpenGL3_Init(const char *glsl_version)
{
imgui_impl_opengl::ImGui_ImplOpenGL3_Init(glsl_version);
BuildShader();
glGenFramebuffers(1, &readbackFramebuffer);
return true;
}
void ImplOpenGl3_Shutdown()
{
// No need to call ImGui_ImplOpenGL3_Shutdown, it doesn't even
// exist in the imgui_impl_opengl namespace. Our version of
// ImGui_ImplOpenGL3_Init doesn't affect OpenGL state.
glDeleteShader(g_VertHandle);
glDeleteShader(g_FragHandle);
glDeleteProgram(g_ShaderHandle);
g_VertHandle = 0;
g_FragHandle = 0;
g_ShaderHandle = 0;
glDeleteFramebuffers(1, &readbackFramebuffer);
readbackFramebuffer = 0;
}
void GiveNotInitializedWarning()
{
static bool warningGiven = false;
if (!warningGiven)
{
fprintf(stderr, "ERROR: ImGuiTexInspect backend not initialized\n");
warningGiven = true;
}
}
//-------------------------------------------------------------------------
// [SECTION] BackEnd functions declared in imgui_tex_inspect_internal.h
//-------------------------------------------------------------------------
void BackEnd_SetShader(const ImDrawList *, const ImDrawCmd *, const Inspector *inspector)
{
const ShaderOptions *texConversion = &inspector->CachedShaderOptions;
if (g_ShaderHandle)
{
ImDrawData *draw_data = ImGui::GetDrawData();
int fb_width = (int)(draw_data->DisplaySize.x * draw_data->FramebufferScale.x);
int fb_height = (int)(draw_data->DisplaySize.y * draw_data->FramebufferScale.y);
if (fb_width <= 0 || fb_height <= 0)
return;
// Setup normal ImGui GL state
ImGui_ImplOpenGL3_SetupRenderState(draw_data, fb_width, fb_height);
// Setup imgui_tex_inspect specific shader uniforms
glUniformMatrix4fv(g_UniformLocationColorTransform, 1, GL_FALSE, texConversion->ColorTransform);
glUniform2fv(g_UniformLocationTextureSize, 1, &inspector->TextureSize.x);
glUniform4fv(g_UniformLocationColorOffset, 1, texConversion->ColorOffset);
glUniform3fv(g_UniformLocationBackgroundColor, 1, &texConversion->BackgroundColor.x);
glUniform1f(g_UniformLocationPremultiplyAlpha, texConversion->PremultiplyAlpha);
glUniform1f(g_UniformLocationDisableFinalAlpha, texConversion->DisableFinalAlpha);
glUniform1i(g_UniformLocationForceNearestSampling, texConversion->ForceNearestSampling);
glUniform2fv(g_UniformLocationGridWidth, 1, &texConversion->GridWidth.x);
glUniform4fv(g_UniformLocationGrid, 1, &texConversion->GridColor.x);
}
else
{
GiveNotInitializedWarning();
}
}
bool BackEnd_GetData(Inspector *inspector, ImTextureID texture, int /*x*/, int /*y*/, int /*width*/, int /*height*/, BufferDesc *bufferDesc)
{
// Current simple implementation just gets data for whole texture
if (readbackFramebuffer == 0)
{
GiveNotInitializedWarning();
return false;
}
const int numChannels = 4;
glGetError(); // Discard any current error so that check at end of function is useful
void * data;
int texWidth = (int)inspector->TextureSize.x;
int texHeight = (int)inspector->TextureSize.y;
GLuint glTexture = (GLuint)(uintptr_t)texture; //Double cast to avoid warning
#ifdef IMGUI_TEX_INSPECT_FLOAT_READ_ENABLED
size_t bufferSize = sizeof(float) * texWidth * texHeight * numChannels;
bufferDesc->Data_float = (float *)GetBuffer(inspector, bufferSize);
GLuint type = GL_FLOAT;
data = (void *)bufferDesc->Data_float;
#else
size_t bufferSize = sizeof(uint8_t) * texWidth * texHeight * numChannels;
bufferDesc->Data_uint8_t = (uint8_t *)GetBuffer(inspector, bufferSize);
GLuint type = GL_UNSIGNED_BYTE;
data = (void *)bufferDesc->Data_uint8_t;
#endif
if (data == NULL)
return false;
bufferDesc->BufferByteSize = bufferSize;
bufferDesc->Red = 0; // Data is packed such that red channel is first
bufferDesc->Green = 1; // then green, then blue, the alpha. Hence, 0,1,2,3
bufferDesc->Blue = 2; // for these channel order values.
bufferDesc->Alpha = 3;
bufferDesc->ChannelCount = 4; // RGBA
bufferDesc->LineStride = (int)inspector->TextureSize.x * numChannels;
bufferDesc->Stride = 4; // No padding between each RGBA texel
bufferDesc->StartX = 0; // We queried the whole texture
bufferDesc->StartY = 0;
bufferDesc->Width = texWidth;
bufferDesc->Height = texHeight;
// Save current frame buffer so we can restore it
GLuint currentFramebuffer;
glGetIntegerv(GL_FRAMEBUFFER_BINDING, (GLint *)&currentFramebuffer);
// Read texture data
glBindFramebuffer(GL_FRAMEBUFFER, readbackFramebuffer);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, glTexture, 0);
glReadPixels(0, 0, texWidth, texHeight, GL_RGBA, type, data);
// Restore previous framebuffer
glBindFramebuffer(GL_FRAMEBUFFER, currentFramebuffer);
return glGetError() == GL_NO_ERROR;
}
} // namespace ImGuiTexInspect