SDL_shaders_gl.c
Go to the documentation of this file.
/*
Simple DirectMedia Layer
Copyright (C) 1997-2018 Sam Lantinga <slouken@libsdl.org>
This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.
Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:
1. The origin of this software must not be misrepresented; you must not
claim that you wrote the original software. If you use this software
in a product, an acknowledgment in the product documentation would be
appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be
misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/
#include "../../SDL_internal.h"
#if SDL_VIDEO_RENDER_OGL && !SDL_RENDER_DISABLED
#include "SDL_stdinc.h"
#include "SDL_log.h"
#include "SDL_opengl.h"
#include "SDL_video.h"
#include "SDL_shaders_gl.h"
/* OpenGL shader implementation */
/* #define DEBUG_SHADERS */
typedef struct
{
GLhandleARB program;
GLhandleARB vert_shader;
GLhandleARB frag_shader;
} GL_ShaderData;
struct GL_ShaderContext
{
GLenum (*glGetError)(void);
PFNGLATTACHOBJECTARBPROC glAttachObjectARB;
PFNGLCOMPILESHADERARBPROC glCompileShaderARB;
PFNGLCREATEPROGRAMOBJECTARBPROC glCreateProgramObjectARB;
PFNGLCREATESHADEROBJECTARBPROC glCreateShaderObjectARB;
PFNGLDELETEOBJECTARBPROC glDeleteObjectARB;
PFNGLGETINFOLOGARBPROC glGetInfoLogARB;
PFNGLGETOBJECTPARAMETERIVARBPROC glGetObjectParameterivARB;
PFNGLGETUNIFORMLOCATIONARBPROC glGetUniformLocationARB;
PFNGLLINKPROGRAMARBPROC glLinkProgramARB;
PFNGLSHADERSOURCEARBPROC glShaderSourceARB;
PFNGLUNIFORM1IARBPROC glUniform1iARB;
PFNGLUNIFORM1FARBPROC glUniform1fARB;
PFNGLUSEPROGRAMOBJECTARBPROC glUseProgramObjectARB;
SDL_bool GL_ARB_texture_rectangle_supported;
GL_ShaderData shaders[NUM_SHADERS];
};
#define COLOR_VERTEX_SHADER \
"varying vec4 v_color;\n" \
"\n" \
"void main()\n" \
"{\n" \
" gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;\n" \
" v_color = gl_Color;\n" \
"}" \
#define TEXTURE_VERTEX_SHADER \
"varying vec4 v_color;\n" \
"varying vec2 v_texCoord;\n" \
"\n" \
"void main()\n" \
"{\n" \
" gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;\n" \
" v_color = gl_Color;\n" \
" v_texCoord = vec2(gl_MultiTexCoord0);\n" \
"}" \
#define JPEG_SHADER_CONSTANTS \
"// YUV offset \n" \
"const vec3 offset = vec3(0, -0.501960814, -0.501960814);\n" \
"\n" \
"// RGB coefficients \n" \
"const vec3 Rcoeff = vec3(1, 0.000, 1.402);\n" \
"const vec3 Gcoeff = vec3(1, -0.3441, -0.7141);\n" \
"const vec3 Bcoeff = vec3(1, 1.772, 0.000);\n" \
#define BT601_SHADER_CONSTANTS \
"// YUV offset \n" \
"const vec3 offset = vec3(-0.0627451017, -0.501960814, -0.501960814);\n" \
"\n" \
"// RGB coefficients \n" \
"const vec3 Rcoeff = vec3(1.1644, 0.000, 1.596);\n" \
"const vec3 Gcoeff = vec3(1.1644, -0.3918, -0.813);\n" \
"const vec3 Bcoeff = vec3(1.1644, 2.0172, 0.000);\n" \
#define BT709_SHADER_CONSTANTS \
"// YUV offset \n" \
"const vec3 offset = vec3(-0.0627451017, -0.501960814, -0.501960814);\n" \
"\n" \
"// RGB coefficients \n" \
"const vec3 Rcoeff = vec3(1.1644, 0.000, 1.7927);\n" \
"const vec3 Gcoeff = vec3(1.1644, -0.2132, -0.5329);\n" \
"const vec3 Bcoeff = vec3(1.1644, 2.1124, 0.000);\n" \
#define YUV_SHADER_PROLOGUE \
"varying vec4 v_color;\n" \
"varying vec2 v_texCoord;\n" \
"uniform sampler2D tex0; // Y \n" \
"uniform sampler2D tex1; // U \n" \
"uniform sampler2D tex2; // V \n" \
"\n" \
#define YUV_SHADER_BODY \
"\n" \
"void main()\n" \
"{\n" \
" vec2 tcoord;\n" \
" vec3 yuv, rgb;\n" \
"\n" \
" // Get the Y value \n" \
" tcoord = v_texCoord;\n" \
" yuv.x = texture2D(tex0, tcoord).r;\n" \
"\n" \
" // Get the U and V values \n" \
" tcoord *= UVCoordScale;\n" \
" yuv.y = texture2D(tex1, tcoord).r;\n" \
" yuv.z = texture2D(tex2, tcoord).r;\n" \
"\n" \
" // Do the color transform \n" \
" yuv += offset;\n" \
" rgb.r = dot(yuv, Rcoeff);\n" \
" rgb.g = dot(yuv, Gcoeff);\n" \
" rgb.b = dot(yuv, Bcoeff);\n" \
"\n" \
" // That was easy. :) \n" \
" gl_FragColor = vec4(rgb, 1.0) * v_color;\n" \
"}" \
#define NV12_SHADER_PROLOGUE \
"varying vec4 v_color;\n" \
"varying vec2 v_texCoord;\n" \
"uniform sampler2D tex0; // Y \n" \
"uniform sampler2D tex1; // U/V \n" \
"\n" \
#define NV12_SHADER_BODY \
"\n" \
"void main()\n" \
"{\n" \
" vec2 tcoord;\n" \
" vec3 yuv, rgb;\n" \
"\n" \
" // Get the Y value \n" \
" tcoord = v_texCoord;\n" \
" yuv.x = texture2D(tex0, tcoord).r;\n" \
"\n" \
" // Get the U and V values \n" \
" tcoord *= UVCoordScale;\n" \
" yuv.yz = texture2D(tex1, tcoord).ra;\n" \
"\n" \
" // Do the color transform \n" \
" yuv += offset;\n" \
" rgb.r = dot(yuv, Rcoeff);\n" \
" rgb.g = dot(yuv, Gcoeff);\n" \
" rgb.b = dot(yuv, Bcoeff);\n" \
"\n" \
" // That was easy. :) \n" \
" gl_FragColor = vec4(rgb, 1.0) * v_color;\n" \
"}" \
#define NV21_SHADER_PROLOGUE \
"varying vec4 v_color;\n" \
"varying vec2 v_texCoord;\n" \
"uniform sampler2D tex0; // Y \n" \
"uniform sampler2D tex1; // U/V \n" \
"\n" \
#define NV21_SHADER_BODY \
"\n" \
"void main()\n" \
"{\n" \
" vec2 tcoord;\n" \
" vec3 yuv, rgb;\n" \
"\n" \
" // Get the Y value \n" \
" tcoord = v_texCoord;\n" \
" yuv.x = texture2D(tex0, tcoord).r;\n" \
"\n" \
" // Get the U and V values \n" \
" tcoord *= UVCoordScale;\n" \
" yuv.yz = texture2D(tex1, tcoord).ar;\n" \
"\n" \
" // Do the color transform \n" \
" yuv += offset;\n" \
" rgb.r = dot(yuv, Rcoeff);\n" \
" rgb.g = dot(yuv, Gcoeff);\n" \
" rgb.b = dot(yuv, Bcoeff);\n" \
"\n" \
" // That was easy. :) \n" \
" gl_FragColor = vec4(rgb, 1.0) * v_color;\n" \
"}" \
/*
* NOTE: Always use sampler2D, etc here. We'll #define them to the
* texture_rectangle versions if we choose to use that extension.
*/
static const char *shader_source[NUM_SHADERS][2] =
{
/* SHADER_NONE */
{ NULL, NULL },
/* SHADER_SOLID */
{
/* vertex shader */
COLOR_VERTEX_SHADER,
/* fragment shader */
"varying vec4 v_color;\n"
"\n"
"void main()\n"
"{\n"
" gl_FragColor = v_color;\n"
"}"
},
/* SHADER_RGB */
{
/* vertex shader */
TEXTURE_VERTEX_SHADER,
/* fragment shader */
"varying vec4 v_color;\n"
"varying vec2 v_texCoord;\n"
"uniform sampler2D tex0;\n"
"\n"
"void main()\n"
"{\n"
" gl_FragColor = texture2D(tex0, v_texCoord) * v_color;\n"
"}"
},
/* SHADER_YUV_JPEG */
{
/* vertex shader */
TEXTURE_VERTEX_SHADER,
/* fragment shader */
YUV_SHADER_PROLOGUE
JPEG_SHADER_CONSTANTS
YUV_SHADER_BODY
},
/* SHADER_YUV_BT601 */
{
/* vertex shader */
TEXTURE_VERTEX_SHADER,
/* fragment shader */
YUV_SHADER_PROLOGUE
BT601_SHADER_CONSTANTS
YUV_SHADER_BODY
},
/* SHADER_YUV_BT709 */
{
/* vertex shader */
TEXTURE_VERTEX_SHADER,
/* fragment shader */
YUV_SHADER_PROLOGUE
BT709_SHADER_CONSTANTS
YUV_SHADER_BODY
},
/* SHADER_NV12_JPEG */
{
/* vertex shader */
TEXTURE_VERTEX_SHADER,
/* fragment shader */
NV12_SHADER_PROLOGUE
JPEG_SHADER_CONSTANTS
NV12_SHADER_BODY
},
/* SHADER_NV12_BT601 */
{
/* vertex shader */
TEXTURE_VERTEX_SHADER,
/* fragment shader */
NV12_SHADER_PROLOGUE
BT601_SHADER_CONSTANTS
NV12_SHADER_BODY
},
/* SHADER_NV12_BT709 */
{
/* vertex shader */
TEXTURE_VERTEX_SHADER,
/* fragment shader */
NV12_SHADER_PROLOGUE
BT709_SHADER_CONSTANTS
NV12_SHADER_BODY
},
/* SHADER_NV21_JPEG */
{
/* vertex shader */
TEXTURE_VERTEX_SHADER,
/* fragment shader */
NV21_SHADER_PROLOGUE
JPEG_SHADER_CONSTANTS
NV21_SHADER_BODY
},
/* SHADER_NV21_BT601 */
{
/* vertex shader */
TEXTURE_VERTEX_SHADER,
/* fragment shader */
NV21_SHADER_PROLOGUE
BT601_SHADER_CONSTANTS
NV21_SHADER_BODY
},
/* SHADER_NV21_BT709 */
{
/* vertex shader */
TEXTURE_VERTEX_SHADER,
/* fragment shader */
NV21_SHADER_PROLOGUE
BT709_SHADER_CONSTANTS
NV21_SHADER_BODY
},
};
static SDL_bool
CompileShader(GL_ShaderContext *ctx, GLhandleARB shader, const char *defines, const char *source)
{
GLint status;
const char *sources[2];
sources[0] = defines;
sources[1] = source;
ctx->glShaderSourceARB(shader, SDL_arraysize(sources), sources, NULL);
ctx->glCompileShaderARB(shader);
ctx->glGetObjectParameterivARB(shader, GL_OBJECT_COMPILE_STATUS_ARB, &status);
if (status == 0) {
GLint length;
char *info;
ctx->glGetObjectParameterivARB(shader, GL_OBJECT_INFO_LOG_LENGTH_ARB, &length);
info = SDL_stack_alloc(char, length+1);
ctx->glGetInfoLogARB(shader, length, NULL, info);
SDL_LogError(SDL_LOG_CATEGORY_RENDER,
"Failed to compile shader:\n%s%s\n%s", defines, source, info);
#ifdef DEBUG_SHADERS
fprintf(stderr,
"Failed to compile shader:\n%s%s\n%s", defines, source, info);
#endif
SDL_stack_free(info);
return SDL_FALSE;
} else {
return SDL_TRUE;
}
}
static SDL_bool
CompileShaderProgram(GL_ShaderContext *ctx, int index, GL_ShaderData *data)
{
const int num_tmus_bound = 4;
const char *vert_defines = "";
const char *frag_defines = "";
int i;
GLint location;
if (index == SHADER_NONE) {
return SDL_TRUE;
}
ctx->glGetError();
/* Make sure we use the correct sampler type for our texture type */
if (ctx->GL_ARB_texture_rectangle_supported) {
frag_defines =
"#define sampler2D sampler2DRect\n"
"#define texture2D texture2DRect\n"
"#define UVCoordScale 0.5\n";
} else {
frag_defines =
"#define UVCoordScale 1.0\n";
}
/* Create one program object to rule them all */
data->program = ctx->glCreateProgramObjectARB();
/* Create the vertex shader */
data->vert_shader = ctx->glCreateShaderObjectARB(GL_VERTEX_SHADER_ARB);
if (!CompileShader(ctx, data->vert_shader, vert_defines, shader_source[index][0])) {
return SDL_FALSE;
}
/* Create the fragment shader */
data->frag_shader = ctx->glCreateShaderObjectARB(GL_FRAGMENT_SHADER_ARB);
if (!CompileShader(ctx, data->frag_shader, frag_defines, shader_source[index][1])) {
return SDL_FALSE;
}
/* ... and in the darkness bind them */
ctx->glAttachObjectARB(data->program, data->vert_shader);
ctx->glAttachObjectARB(data->program, data->frag_shader);
ctx->glLinkProgramARB(data->program);
/* Set up some uniform variables */
ctx->glUseProgramObjectARB(data->program);
for (i = 0; i < num_tmus_bound; ++i) {
char tex_name[10];
SDL_snprintf(tex_name, SDL_arraysize(tex_name), "tex%d", i);
location = ctx->glGetUniformLocationARB(data->program, tex_name);
if (location >= 0) {
ctx->glUniform1iARB(location, i);
}
}
ctx->glUseProgramObjectARB(0);
return (ctx->glGetError() == GL_NO_ERROR);
}
static void
DestroyShaderProgram(GL_ShaderContext *ctx, GL_ShaderData *data)
{
ctx->glDeleteObjectARB(data->vert_shader);
ctx->glDeleteObjectARB(data->frag_shader);
ctx->glDeleteObjectARB(data->program);
}
GL_ShaderContext *
GL_CreateShaderContext(void)
{
GL_ShaderContext *ctx;
SDL_bool shaders_supported;
int i;
ctx = (GL_ShaderContext *)SDL_calloc(1, sizeof(*ctx));
if (!ctx) {
return NULL;
}
if (!SDL_GL_ExtensionSupported("GL_ARB_texture_non_power_of_two") &&
(SDL_GL_ExtensionSupported("GL_ARB_texture_rectangle") ||
SDL_GL_ExtensionSupported("GL_EXT_texture_rectangle"))) {
ctx->GL_ARB_texture_rectangle_supported = SDL_TRUE;
}
/* Check for shader support */
shaders_supported = SDL_FALSE;
if (SDL_GL_ExtensionSupported("GL_ARB_shader_objects") &&
SDL_GL_ExtensionSupported("GL_ARB_shading_language_100") &&
SDL_GL_ExtensionSupported("GL_ARB_vertex_shader") &&
SDL_GL_ExtensionSupported("GL_ARB_fragment_shader")) {
ctx->glGetError = (GLenum (*)(void)) SDL_GL_GetProcAddress("glGetError");
ctx->glAttachObjectARB = (PFNGLATTACHOBJECTARBPROC) SDL_GL_GetProcAddress("glAttachObjectARB");
ctx->glCompileShaderARB = (PFNGLCOMPILESHADERARBPROC) SDL_GL_GetProcAddress("glCompileShaderARB");
ctx->glCreateProgramObjectARB = (PFNGLCREATEPROGRAMOBJECTARBPROC) SDL_GL_GetProcAddress("glCreateProgramObjectARB");
ctx->glCreateShaderObjectARB = (PFNGLCREATESHADEROBJECTARBPROC) SDL_GL_GetProcAddress("glCreateShaderObjectARB");
ctx->glDeleteObjectARB = (PFNGLDELETEOBJECTARBPROC) SDL_GL_GetProcAddress("glDeleteObjectARB");
ctx->glGetInfoLogARB = (PFNGLGETINFOLOGARBPROC) SDL_GL_GetProcAddress("glGetInfoLogARB");
ctx->glGetObjectParameterivARB = (PFNGLGETOBJECTPARAMETERIVARBPROC) SDL_GL_GetProcAddress("glGetObjectParameterivARB");
ctx->glGetUniformLocationARB = (PFNGLGETUNIFORMLOCATIONARBPROC) SDL_GL_GetProcAddress("glGetUniformLocationARB");
ctx->glLinkProgramARB = (PFNGLLINKPROGRAMARBPROC) SDL_GL_GetProcAddress("glLinkProgramARB");
ctx->glShaderSourceARB = (PFNGLSHADERSOURCEARBPROC) SDL_GL_GetProcAddress("glShaderSourceARB");
ctx->glUniform1iARB = (PFNGLUNIFORM1IARBPROC) SDL_GL_GetProcAddress("glUniform1iARB");
ctx->glUniform1fARB = (PFNGLUNIFORM1FARBPROC) SDL_GL_GetProcAddress("glUniform1fARB");
ctx->glUseProgramObjectARB = (PFNGLUSEPROGRAMOBJECTARBPROC) SDL_GL_GetProcAddress("glUseProgramObjectARB");
if (ctx->glGetError &&
ctx->glAttachObjectARB &&
ctx->glCompileShaderARB &&
ctx->glCreateProgramObjectARB &&
ctx->glCreateShaderObjectARB &&
ctx->glDeleteObjectARB &&
ctx->glGetInfoLogARB &&
ctx->glGetObjectParameterivARB &&
ctx->glGetUniformLocationARB &&
ctx->glLinkProgramARB &&
ctx->glShaderSourceARB &&
ctx->glUniform1iARB &&
ctx->glUniform1fARB &&
ctx->glUseProgramObjectARB) {
shaders_supported = SDL_TRUE;
}
}
if (!shaders_supported) {
SDL_free(ctx);
return NULL;
}
/* Compile all the shaders */
for (i = 0; i < NUM_SHADERS; ++i) {
if (!CompileShaderProgram(ctx, i, &ctx->shaders[i])) {
GL_DestroyShaderContext(ctx);
return NULL;
}
}
/* We're done! */
return ctx;
}
void
GL_SelectShader(GL_ShaderContext *ctx, GL_Shader shader)
{
ctx->glUseProgramObjectARB(ctx->shaders[shader].program);
}
void
GL_DestroyShaderContext(GL_ShaderContext *ctx)
{
int i;
for (i = 0; i < NUM_SHADERS; ++i) {
DestroyShaderProgram(ctx, &ctx->shaders[i]);
}
SDL_free(ctx);
}
#endif /* SDL_VIDEO_RENDER_OGL && !SDL_RENDER_DISABLED */
/* vi: set ts=4 sw=4 expandtab: */
SDL_GL_ExtensionSupported
#define SDL_GL_ExtensionSupported
Definition: SDL_dynapi_overrides.h:556
GL_CreateShaderContext
GL_ShaderContext * GL_CreateShaderContext(void)
SDL_TRUE
Definition: SDL_stdinc.h:142
sources
GLsizei GLenum * sources
Definition: SDL_opengl_glext.h:2482
SDL_log.h
SDL_FALSE
Definition: SDL_stdinc.h:141
GLint
int GLint
Definition: SDL_opengl.h:182
data
GLint GLenum GLsizei GLsizei GLsizei GLint GLsizei const GLvoid * data
Definition: SDL_opengl.h:1974
GL_VERTEX_SHADER_ARB
#define GL_VERTEX_SHADER_ARB
Definition: SDL_opengl_glext.h:4322
shaders
GLsizei GLsizei GLuint * shaders
Definition: SDL_opengl_glext.h:671
GLhandleARB
unsigned int GLhandleARB
Definition: SDL_opengl_glext.h:3575
GL_ShaderContext
struct GL_ShaderContext GL_ShaderContext
Definition: SDL_shaders_gl.h:41
GL_DestroyShaderContext
void GL_DestroyShaderContext(GL_ShaderContext *ctx)
SDL_LogError
#define SDL_LogError
Definition: SDL_dynapi_overrides.h:36
GL_NO_ERROR
#define GL_NO_ERROR
Definition: SDL_opengl.h:719
SDL_opengl.h
SDL_video.h
GL_Shader
GL_Shader
Definition: SDL_shaders_gl.h:25
SDL_free
#define SDL_free
Definition: SDL_dynapi_overrides.h:377
SDL_stack_alloc
#define SDL_stack_alloc(type, count)
Definition: SDL_stdinc.h:354
SDL_GL_GetProcAddress
#define SDL_GL_GetProcAddress
Definition: SDL_dynapi_overrides.h:554
location
GLint location
Definition: SDL_opengl_glext.h:679
GL_OBJECT_INFO_LOG_LENGTH_ARB
#define GL_OBJECT_INFO_LOG_LENGTH_ARB
Definition: SDL_opengl_glext.h:3607
SDL_shaders_gl.h
GL_OBJECT_COMPILE_STATUS_ARB
#define GL_OBJECT_COMPILE_STATUS_ARB
Definition: SDL_opengl_glext.h:3604
source
GLsizei GLsizei GLchar * source
Definition: SDL_opengl_glext.h:677
index
GLuint index
Definition: SDL_opengl_glext.h:660
GL_FRAGMENT_SHADER_ARB
#define GL_FRAGMENT_SHADER_ARB
Definition: SDL_opengl_glext.h:2974
i
return Display return Display Bool Bool int int int return Display XEvent Bool(*) XPointer return Display return Display Drawable _Xconst char unsigned int unsigned int return Display Pixmap Pixmap XColor XColor unsigned int unsigned int return Display _Xconst char char int char return Display Visual unsigned int int int char unsigned int unsigned int in i)
Definition: SDL_x11sym.h:50
GLenum
unsigned int GLenum
Definition: SDL_opengl.h:176
NULL
#define NULL
Definition: begin_code.h:164
SDL_bool
SDL_bool
Definition: SDL_stdinc.h:139
SDL_calloc
#define SDL_calloc
Definition: SDL_dynapi_overrides.h:375
SDL_stdinc.h
void
SDL_PRINTF_FORMAT_STRING const char int SDL_PRINTF_FORMAT_STRING const char int SDL_PRINTF_FORMAT_STRING const char int SDL_PRINTF_FORMAT_STRING const char const char SDL_SCANF_FORMAT_STRING const char return SDL_ThreadFunction const char void return Uint32 return Uint32 void
Definition: SDL_dynapi_procs.h:89
glGetError
GLAPI GLenum GLAPIENTRY glGetError(void)
SDL_snprintf
#define SDL_snprintf
Definition: SDL_dynapi_overrides.h:40
SHADER_NONE
Definition: SDL_shaders_gl.h:26
SDL_arraysize
#define SDL_arraysize(array)
Definition: SDL_stdinc.h:93
program
GLbitfield GLuint program
Definition: SDL_opengl_glext.h:1875
SDL_stack_free
#define SDL_stack_free(data)
Definition: SDL_stdinc.h:355
length
GLuint GLsizei GLsizei * length
Definition: SDL_opengl_glext.h:669
SDL_LOG_CATEGORY_RENDER
Definition: SDL_log.h:72
GL_SelectShader
void GL_SelectShader(GL_ShaderContext *ctx, GL_Shader shader)
shader
GLuint shader
Definition: SDL_opengl_glext.h:659
NUM_SHADERS
Definition: SDL_shaders_d3d.h:29
ctx
EGLContext ctx
Definition: eglext.h:208