/*

SDL - Simple DirectMedia Layer

Copyright (C) 1997-2010 Sam Lantinga

This library is free software; you can redistribute it and/or

modify it under the terms of the GNU Lesser General Public

License as published by the Free Software Foundation; either

version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,

but WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU

Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public

License along with this library; if not, write to the Free Software

Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA

Sam Lantinga

slouken@libsdl.org

*/

#include "SDL_config.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

{

GLenum program;

GLenum vert_shader;

GLenum 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_Shader current_shader;

GL_ShaderData shaders[NUM_SHADERS];

};

/*

* 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 */

"varying vec4 v_color;\n"

"\n"

"void main()\n"

"{\n"

" gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;\n"

" v_color = gl_Color;\n"

"}",

"varying vec4 v_color;\n"

"\n"

"void main()\n"

"{\n"

" gl_FragColor = v_color;\n"

"}"

},

/* SHADER_RGB */

{

/* 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"

"}",

"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"

"}"

},

};

static SDL_bool

{

GLint status;

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";

}

/* 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);

return SDL_FALSE;

}

/* Create the fragment shader */

data->frag_shader = ctx->glCreateShaderObjectARB(GL_FRAGMENT_SHADER_ARB);

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[5];

SDL_snprintf(tex_name, SDL_arraysize(tex_name), "tex%d", i);

location = ctx->glGetUniformLocationARB(data->program, tex_name);

if (location >= 0) {

}

}

ctx->glUseProgramObjectARB(0);

return (ctx->glGetError() == GL_NO_ERROR);

}

static void

DestroyShaderProgram(GL_ShaderContext *ctx, GL_ShaderData *data)

{

if (index == SHADER_NONE) {

return;

}

ctx->glDeleteObjectARB(data->vert_shader);

ctx->glDeleteObjectARB(data->frag_shader);

ctx->glDeleteObjectARB(data->program);

}

GL_ShaderContext *

GL_CreateShaderContext()

{

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_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) {

return NULL;

}

/* Compile all the shaders */

for (i = 0; i < NUM_SHADERS; ++i) {

if (!CompileShaderProgram(ctx, i, &ctx->shaders[i])) {

fprintf(stderr, "Unable to compile shader!\n");

GL_DestroyShaderContext(ctx);

return NULL;

}

}

/* We're done! */

return ctx;

}

void

GL_SelectShader(GL_ShaderContext *ctx, GL_Shader shader)

{

/* Nothing to do if there's no shader support */

if (!ctx) {

return;

}

/* Nothing to do if there's no shader change */

if (shader == ctx->current_shader) {

return;

}

ctx->glUseProgramObjectARB(ctx->shaders[shader].program);

ctx->current_shader = shader;

}

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: */