/*

    SDL - Simple DirectMedia Layer

    Copyright (C) 1997-2006 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_ES

#include "SDL_video.h"

#include "SDL_opengles.h"

#include "SDL_sysvideo.h"

#include "SDL_pixels_c.h"

#include "SDL_rect_c.h"

#include "SDL_yuv_sw_c.h"

/* OpenGL ES 1.1 renderer implementation, based on the OpenGL renderer */

static const float inv255f = 1.0f / 255.0f;

static SDL_Renderer *GLES_CreateRenderer(SDL_Window * window, Uint32 flags);

static int GLES_ActivateRenderer(SDL_Renderer * renderer);

static int GLES_DisplayModeChanged(SDL_Renderer * renderer);

static int GLES_CreateTexture(SDL_Renderer * renderer, SDL_Texture * texture);

static int GLES_QueryTexturePixels(SDL_Renderer * renderer,

                                 SDL_Texture * texture, void **pixels,

                                 int *pitch);

static int GLES_SetTexturePalette(SDL_Renderer * renderer,

                                SDL_Texture * texture,

                                const SDL_Color * colors, int firstcolor,

                                int ncolors);

static int GLES_GetTexturePalette(SDL_Renderer * renderer,

                                SDL_Texture * texture, SDL_Color * colors,

                                int firstcolor, int ncolors);

static int GLES_SetTextureColorMod(SDL_Renderer * renderer,

                                 SDL_Texture * texture);

static int GLES_SetTextureAlphaMod(SDL_Renderer * renderer,

                                 SDL_Texture * texture);

static int GLES_SetTextureBlendMode(SDL_Renderer * renderer,

                                  SDL_Texture * texture);

static int GLES_SetTextureScaleMode(SDL_Renderer * renderer,

                                  SDL_Texture * texture);

static int GLES_UpdateTexture(SDL_Renderer * renderer, SDL_Texture * texture,

                            const SDL_Rect * rect, const void *pixels,

                            int pitch);

static int GLES_LockTexture(SDL_Renderer * renderer, SDL_Texture * texture,

                          const SDL_Rect * rect, int markDirty, void **pixels,

                          int *pitch);

static void GLES_UnlockTexture(SDL_Renderer * renderer, SDL_Texture * texture);

static void GLES_DirtyTexture(SDL_Renderer * renderer, SDL_Texture * texture,

                            int numrects, const SDL_Rect * rects);

static int GLES_RenderFill(SDL_Renderer * renderer, Uint8 r, Uint8 g, Uint8 b,

                         Uint8 a, const SDL_Rect * rect);

static int GLES_RenderCopy(SDL_Renderer * renderer, SDL_Texture * texture,

                         const SDL_Rect * srcrect, const SDL_Rect * dstrect);

static void GLES_RenderPresent(SDL_Renderer * renderer);

static void GLES_DestroyTexture(SDL_Renderer * renderer, SDL_Texture * texture);

static void GLES_DestroyRenderer(SDL_Renderer * renderer);

SDL_RenderDriver GL_ES_RenderDriver = {

    GLES_CreateRenderer,

    {

     "opengl_es",

     (SDL_RENDERER_SINGLEBUFFER | SDL_RENDERER_PRESENTDISCARD |

      SDL_RENDERER_PRESENTVSYNC | SDL_RENDERER_ACCELERATED),

     (SDL_TEXTUREMODULATE_NONE | SDL_TEXTUREMODULATE_COLOR |

      SDL_TEXTUREMODULATE_ALPHA),

     (SDL_TEXTUREBLENDMODE_NONE | SDL_TEXTUREBLENDMODE_MASK |

      SDL_TEXTUREBLENDMODE_BLEND | SDL_TEXTUREBLENDMODE_ADD |

      SDL_TEXTUREBLENDMODE_MOD),

     (SDL_TEXTURESCALEMODE_NONE | SDL_TEXTURESCALEMODE_FAST |

      SDL_TEXTURESCALEMODE_SLOW), 2,

		{

		SDL_PIXELFORMAT_RGB24,

		SDL_PIXELFORMAT_ABGR8888,

		},

	 0,

     0}

};

typedef struct

{

    SDL_GLContext context;

    SDL_bool updateSize;

    int blendMode;

#ifndef APIENTRY

#define APIENTRY

#endif

	SDL_bool useDrawTexture;

	SDL_bool GL_OES_draw_texture_supported;

	/* OpenGL ES functions */

	#define SDL_PROC(ret,func,params) ret (APIENTRY *func) params;

	#include "SDL_glesfuncs.h"

	#undef SDL_PROC

} GLES_RenderData;

typedef struct

{

    GLuint texture;

    GLenum type;

    GLfloat texw;

    GLfloat texh;

    GLenum format;

    GLenum formattype;

    void *pixels;

    int pitch;

    SDL_DirtyRectList dirty;

} GLES_TextureData;

static void

GLES_SetError(const char *prefix, GLenum result)

{

    const char *error;

    switch (result) {

    case GL_NO_ERROR:

        error = "GL_NO_ERROR";

        break;

    case GL_INVALID_ENUM:

        error = "GL_INVALID_ENUM";

        break;

    case GL_INVALID_VALUE:

        error = "GL_INVALID_VALUE";

        break;

    case GL_INVALID_OPERATION:

        error = "GL_INVALID_OPERATION";

        break;

    case GL_STACK_OVERFLOW:

        error = "GL_STACK_OVERFLOW";

        break;

    case GL_STACK_UNDERFLOW:

        error = "GL_STACK_UNDERFLOW";

        break;

    case GL_OUT_OF_MEMORY:

        error = "GL_OUT_OF_MEMORY";

        break;

    default:

        error = "UNKNOWN";

        break;

    }

    SDL_SetError("%s: %s", prefix, error);

}

static int

GLES_LoadFunctions(GLES_RenderData * data)

{

	#define SDL_PROC(ret,func,params) \

	data->func = func;

	#include "SDL_glesfuncs.h"

	#undef SDL_PROC

    return 0;

}

void

GLES_AddRenderDriver(_THIS)

{

    if (_this->GL_CreateContext) {

        SDL_AddRenderDriver(0, &GL_ES_RenderDriver);

    }

}

SDL_Renderer *

GLES_CreateRenderer(SDL_Window * window, Uint32 flags)

{

    SDL_Renderer *renderer;

    GLES_RenderData *data;

    GLint value;

    int doublebuffer;

    if (!(window->flags & SDL_WINDOW_OPENGL)) {

        if (SDL_RecreateWindow(window, window->flags | SDL_WINDOW_OPENGL) < 0) {

            return NULL;

        }

    }

    renderer = (SDL_Renderer *) SDL_calloc(1, sizeof(*renderer));

    if (!renderer) {

        SDL_OutOfMemory();

        return NULL;

    }

    data = (GLES_RenderData *) SDL_calloc(1, sizeof(*data));

    if (!data) {

        GLES_DestroyRenderer(renderer);

        SDL_OutOfMemory();

        return NULL;

    }

    renderer->ActivateRenderer = GLES_ActivateRenderer;

    renderer->DisplayModeChanged = GLES_DisplayModeChanged;

    renderer->CreateTexture = GLES_CreateTexture;

    renderer->QueryTexturePixels = GLES_QueryTexturePixels;

    renderer->SetTexturePalette = GLES_SetTexturePalette;

    renderer->GetTexturePalette = GLES_GetTexturePalette;

    renderer->SetTextureColorMod = GLES_SetTextureColorMod;

    renderer->SetTextureAlphaMod = GLES_SetTextureAlphaMod;

    renderer->SetTextureBlendMode = GLES_SetTextureBlendMode;

    renderer->SetTextureScaleMode = GLES_SetTextureScaleMode;

    renderer->UpdateTexture = GLES_UpdateTexture;

    renderer->LockTexture = GLES_LockTexture;

    renderer->UnlockTexture = GLES_UnlockTexture;

    renderer->DirtyTexture = GLES_DirtyTexture;

    renderer->RenderFill = GLES_RenderFill;

    renderer->RenderCopy = GLES_RenderCopy;

    renderer->RenderPresent = GLES_RenderPresent;

    renderer->DestroyTexture = GLES_DestroyTexture;

    renderer->DestroyRenderer = GLES_DestroyRenderer;

    renderer->info = GL_ES_RenderDriver.info;

    renderer->window = window->id;

    renderer->driverdata = data;

    renderer->info.flags = (SDL_RENDERER_PRESENTDISCARD | SDL_RENDERER_ACCELERATED);

    if (GLES_LoadFunctions(data) < 0) {

        GLES_DestroyRenderer(renderer);

        return NULL;

    }

    data->context = SDL_GL_CreateContext(window->id);

    if (!data->context) {

        GLES_DestroyRenderer(renderer);

        return NULL;

    }

    if (SDL_GL_MakeCurrent(window->id, data->context) < 0) {

        GLES_DestroyRenderer(renderer);

        return NULL;

    }

    if (flags & SDL_RENDERER_PRESENTVSYNC) {

        SDL_GL_SetSwapInterval(1);

    } else {

        SDL_GL_SetSwapInterval(0);

    }

    if (SDL_GL_GetSwapInterval() > 0) {

        renderer->info.flags |= SDL_RENDERER_PRESENTVSYNC;

    }

    if (SDL_GL_GetAttribute(SDL_GL_DOUBLEBUFFER, &doublebuffer) == 0) {

        if (!doublebuffer) {

            renderer->info.flags |= SDL_RENDERER_SINGLEBUFFER;

        }

    }

	if (SDL_GL_ExtensionSupported("GL_OES_draw_texture")) {

		data->GL_OES_draw_texture_supported = SDL_TRUE;

		data->useDrawTexture = SDL_TRUE;

	}

	else {

		data->GL_OES_draw_texture_supported = SDL_FALSE;

		data->useDrawTexture = SDL_FALSE;

	}	

    data->glGetIntegerv(GL_MAX_TEXTURE_SIZE, &value);

    renderer->info.max_texture_width = value;

    data->glGetIntegerv(GL_MAX_TEXTURE_SIZE, &value);

    renderer->info.max_texture_height = value;

    /* Set up parameters for rendering */

    data->blendMode = -1;

    data->glDisable(GL_DEPTH_TEST);

    data->glDisable(GL_CULL_FACE);

	data->glEnable(GL_TEXTURE_2D);

    data->updateSize = SDL_TRUE;

    return renderer;

}

static int GLES_ActivateRenderer(SDL_Renderer * renderer)

{

    GLES_RenderData *data = (GLES_RenderData *)renderer->driverdata;

    SDL_Window *window = SDL_GetWindowFromID(renderer->window);

    if (SDL_GL_MakeCurrent(window->id, data->context) < 0) {

        return -1;

    }

    if (data->updateSize) {

        data->glMatrixMode(GL_PROJECTION);

        data->glLoadIdentity();

        data->glMatrixMode(GL_MODELVIEW);

        data->glLoadIdentity();

        data->glViewport(0, 0, window->w, window->h);

        data->glOrthof(0.0, (GLfloat)window->w, (GLfloat)window->h, 0.0,

                      0.0, 1.0);

        data->updateSize = SDL_FALSE;

    }

    return 0;

}

static int

GLES_DisplayModeChanged(SDL_Renderer * renderer)

{

    GLES_RenderData *data = (GLES_RenderData *) renderer->driverdata;

    data->updateSize = SDL_TRUE;

    return 0;

}

static __inline__ int

power_of_2(int input)

{

    int value = 1;

    while (value < input) {

        value <<= 1;

    }

    return value;

}

static int

GLES_CreateTexture(SDL_Renderer * renderer, SDL_Texture * texture)

{

    GLES_RenderData *renderdata = (GLES_RenderData *) renderer->driverdata;

    SDL_Window *window = SDL_GetWindowFromID(renderer->window);

    GLES_TextureData *data;

    GLint internalFormat;

    GLenum format, type;

    int texture_w, texture_h;

    GLenum result;

	switch (texture->format) {

		case SDL_PIXELFORMAT_INDEX1LSB:

		case SDL_PIXELFORMAT_INDEX1MSB:

		case SDL_PIXELFORMAT_INDEX8:

		case SDL_PIXELFORMAT_RGB332:

		case SDL_PIXELFORMAT_RGB444:

		case SDL_PIXELFORMAT_RGB555:

		case SDL_PIXELFORMAT_ARGB4444:

		case SDL_PIXELFORMAT_ARGB1555:

		case SDL_PIXELFORMAT_BGR24:

		case SDL_PIXELFORMAT_BGR888:

		case SDL_PIXELFORMAT_RGB888:

		case SDL_PIXELFORMAT_RGBA8888:

		case SDL_PIXELFORMAT_ARGB2101010:

		case SDL_PIXELFORMAT_ARGB8888:

		case SDL_PIXELFORMAT_RGB24:

			internalFormat = GL_RGB;

			format = GL_RGB;

			type = GL_UNSIGNED_BYTE;

			break;

		case SDL_PIXELFORMAT_ABGR8888:

			internalFormat = GL_RGBA;

			format = GL_RGBA;

			type = GL_UNSIGNED_BYTE;			

			break;			

		/*

			These formats would be supported if SDL had the necessary pixel formats

		case SDL_PIXELFORMAT_BGR565:

			internalFormat = GL_RGB;

			format = GL_RGB;

			type = GL_UNSIGNED_SHORT_5_6_5;

			break;			

		case SDL_PIXELFORMAT_ABGR5551:

			internalFormat = GL_RGBA;

			format = GL_RGBA;

			type = GL_UNSIGNED_SHORT_5_5_5_1;

			break;

		case SDL_PIXELFORMAT_ABGR4444:

			internalFormat = GL_RGBA;

			format = GL_RGBA;

			type = GL_UNSIGNED_SHORT_4_4_4_4;

			break;

		*/

		default:

			SDL_SetError("Unsupported texture format");

			return -1;

    }

	data = (GLES_TextureData *) SDL_calloc(1, sizeof(*data));

    if (!data) {

        SDL_OutOfMemory();

        return -1;

    }

    if (texture->access == SDL_TEXTUREACCESS_STREAMING) {

        data->pitch = texture->w * SDL_BYTESPERPIXEL(texture->format);

        data->pixels = SDL_malloc(texture->h * data->pitch);

        if (!data->pixels) {

            SDL_OutOfMemory();

            SDL_free(data);

            return -1;

        }

    }

    texture->driverdata = data;

    renderdata->glGetError();

    renderdata->glGenTextures(1, &data->texture);

	data->type = GL_TEXTURE_2D;

	/* no NPOV textures allowed in OpenGL ES (yet) */

	texture_w = power_of_2(texture->w);

	texture_h = power_of_2(texture->h);

	data->texw = (GLfloat) texture->w / texture_w;

	data->texh = (GLfloat) texture->h / texture_h;

    data->format = format;

    data->formattype = type;

    renderdata->glBindTexture(data->type, data->texture);

    renderdata->glTexParameteri(data->type, GL_TEXTURE_MIN_FILTER,

                                GL_NEAREST);

    renderdata->glTexParameteri(data->type, GL_TEXTURE_MAG_FILTER,

                                GL_NEAREST);

    renderdata->glTexParameteri(data->type, GL_TEXTURE_WRAP_S,

                                GL_CLAMP_TO_EDGE);

    renderdata->glTexParameteri(data->type, GL_TEXTURE_WRAP_T,

                                GL_CLAMP_TO_EDGE);

	renderdata->glTexImage2D(data->type, 0, internalFormat, texture_w,

							 texture_h, 0, format, type, NULL);

    result = renderdata->glGetError();

    if (result != GL_NO_ERROR) {

        GLES_SetError("glTexImage2D()", result);

        return -1;

    }

    return 0;

}

static int

GLES_QueryTexturePixels(SDL_Renderer * renderer, SDL_Texture * texture,

                      void **pixels, int *pitch)

{

    GLES_TextureData *data = (GLES_TextureData *) texture->driverdata;

    *pixels = data->pixels;

    *pitch = data->pitch;

    return 0;

}

static int

GLES_SetTexturePalette(SDL_Renderer * renderer, SDL_Texture * texture,

                     const SDL_Color * colors, int firstcolor, int ncolors)

{

	SDL_SetError("OpenGL ES does not support paletted textures");

    return -1;

}

static int

GLES_GetTexturePalette(SDL_Renderer * renderer, SDL_Texture * texture,

                     SDL_Color * colors, int firstcolor, int ncolors)

{

	SDL_SetError("OpenGL ES does not support paletted textures");

    return -1;

}

static void

SetupTextureUpdate(GLES_RenderData * renderdata, SDL_Texture * texture,

                   int pitch)

{

	GLES_TextureData *data = (GLES_TextureData *) texture->driverdata;

	renderdata->glBindTexture(data->type, data->texture);

    renderdata->glPixelStorei(GL_UNPACK_ALIGNMENT, 1);

}

static int

GLES_SetTextureColorMod(SDL_Renderer * renderer, SDL_Texture * texture)

{

    return 0;

}

static int

GLES_SetTextureAlphaMod(SDL_Renderer * renderer, SDL_Texture * texture)

{

    return 0;

}

static int

GLES_SetTextureBlendMode(SDL_Renderer * renderer, SDL_Texture * texture)

{

    switch (texture->blendMode) {

    case SDL_TEXTUREBLENDMODE_NONE:

    case SDL_TEXTUREBLENDMODE_MASK:

    case SDL_TEXTUREBLENDMODE_BLEND:

    case SDL_TEXTUREBLENDMODE_ADD:

    case SDL_TEXTUREBLENDMODE_MOD:

        return 0;

    default:

        SDL_Unsupported();

        texture->blendMode = SDL_TEXTUREBLENDMODE_NONE;

        return -1;

    }

}

static int

GLES_SetTextureScaleMode(SDL_Renderer * renderer, SDL_Texture * texture)

{

    switch (texture->scaleMode) {

    case SDL_TEXTURESCALEMODE_NONE:

    case SDL_TEXTURESCALEMODE_FAST:

    case SDL_TEXTURESCALEMODE_SLOW:

        return 0;

    case SDL_TEXTURESCALEMODE_BEST:

        SDL_Unsupported();

		texture->scaleMode = SDL_TEXTURESCALEMODE_SLOW;

        return -1;

    default:

        SDL_Unsupported();

        texture->scaleMode = SDL_TEXTURESCALEMODE_NONE;

        return -1;

    }

}

static int

GLES_UpdateTexture(SDL_Renderer * renderer, SDL_Texture * texture,

                 const SDL_Rect * rect, const void *pixels, int pitch)

{

    GLES_RenderData *renderdata = (GLES_RenderData *) renderer->driverdata;

    GLES_TextureData *data = (GLES_TextureData *) texture->driverdata;

    GLenum result;

    SetupTextureUpdate(renderdata, texture, pitch);

	renderdata->glGetError();

	renderdata->glTexSubImage2D(data->type, 0, rect->x, rect->y, rect->w,

                                rect->h, data->format, data->formattype,

                                pixels);

    result = renderdata->glGetError();

    if (result != GL_NO_ERROR) {

        GLES_SetError("glTexSubImage2D()", result);

        return -1;

    }

    return 0;

}

static int

GLES_LockTexture(SDL_Renderer * renderer, SDL_Texture * texture,

               const SDL_Rect * rect, int markDirty, void **pixels,

               int *pitch)

{

    GLES_TextureData *data = (GLES_TextureData *) texture->driverdata;

    if (markDirty) {

        SDL_AddDirtyRect(&data->dirty, rect);

    }

    *pixels =

        (void *) ((Uint8 *) data->pixels + rect->y * data->pitch +

                  rect->x * SDL_BYTESPERPIXEL(texture->format));

    *pitch = data->pitch;

    return 0;

}

static void

GLES_UnlockTexture(SDL_Renderer * renderer, SDL_Texture * texture)

{

}

static void

GLES_DirtyTexture(SDL_Renderer * renderer, SDL_Texture * texture, int numrects,

                const SDL_Rect * rects)

{

    GLES_TextureData *data = (GLES_TextureData *) texture->driverdata;

    int i;

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

        SDL_AddDirtyRect(&data->dirty, &rects[i]);

    }

}

static int

GLES_RenderFill(SDL_Renderer * renderer, Uint8 r, Uint8 g, Uint8 b, Uint8 a,

              const SDL_Rect * rect)

{

	GLES_RenderData *data = (GLES_RenderData *) renderer->driverdata;

    SDL_Window *window = SDL_GetWindowFromID(renderer->window);

	/* set proper drawing color */

	GLfloat oldClearColor[4];

	data->glGetFloatv(GL_COLOR_CLEAR_VALUE, oldClearColor);

	data->glClearColor((GLclampf) r * inv255f, (GLclampf) g * inv255f,

			  (GLclampf) b * inv255f, (GLclampf) a * inv255f);

	data->glScissor(rect->x, window->h - rect->y - rect->h, rect->w, rect->h);

	data->glEnable(GL_SCISSOR_TEST);

	data->glClear(GL_COLOR_BUFFER_BIT);

	data->glDisable(GL_SCISSOR_TEST);

	/* reset clear color */

	data->glClearColor(oldClearColor[0], oldClearColor[1], oldClearColor[2], oldClearColor[2]);

	return 0;

}

static int

GLES_RenderCopy(SDL_Renderer * renderer, SDL_Texture * texture,

              const SDL_Rect * srcrect, const SDL_Rect * dstrect)

{

    GLES_RenderData *data = (GLES_RenderData *) renderer->driverdata;

    GLES_TextureData *texturedata = (GLES_TextureData *) texture->driverdata;

    int minx, miny, maxx, maxy;

    GLfloat minu, maxu, minv, maxv;

	int i;

	void *temp_buffer; /* used for reformatting dirty rect pixels */

	void *temp_ptr;

    if (texturedata->dirty.list) {

        SDL_DirtyRect *dirty;

        void *pixels;

        int bpp = SDL_BYTESPERPIXEL(texture->format);

        int pitch = texturedata->pitch;

        SetupTextureUpdate(data, texture, pitch);

        data->glBindTexture(texturedata->type, texturedata->texture);

        for (dirty = texturedata->dirty.list; dirty; dirty = dirty->next) {

            SDL_Rect *rect = &dirty->rect;

            pixels = (void *) ((Uint8 *) texturedata->pixels + rect->y * pitch + rect->x * bpp);

			/*	There is no GL_UNPACK_ROW_LENGTH in OpenGLES 

				we must do this reformatting ourselves(!)

				maybe it'd be a good idea to keep a temp buffer around

				for this purpose rather than allocating it each time

			*/

			temp_buffer = SDL_malloc(rect->w * rect->h * bpp);

			temp_ptr = temp_buffer;

			for (i=0; i<rect->h; i++) {

				SDL_memcpy(temp_ptr, pixels, rect->w * bpp);

				temp_ptr += rect->w * bpp;

				pixels	 += pitch;

			}

            data->glTexSubImage2D(texturedata->type, 0, rect->x, rect->y,

                                  rect->w, rect->h, texturedata->format,

                                  texturedata->formattype, temp_buffer);

			SDL_free(temp_buffer);

        }

        SDL_ClearDirtyRects(&texturedata->dirty);

    }

    data->glBindTexture(texturedata->type, texturedata->texture);

	data->glEnable(GL_TEXTURE_2D);

    if (texture->modMode) {

        data->glColor4f((GLfloat) texture->r * inv255f,

                        (GLfloat) texture->g * inv255f,

                        (GLfloat) texture->b * inv255f,

                        (GLfloat) texture->a * inv255f);

    } else {

        data->glColor4f(1.0f, 1.0f, 1.0f, 1.0f);

    }

    if (texture->blendMode != data->blendMode) {

        switch (texture->blendMode) {

        case SDL_TEXTUREBLENDMODE_NONE:

            data->glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL);

            data->glDisable(GL_BLEND);

            break;

        case SDL_TEXTUREBLENDMODE_MASK:

        case SDL_TEXTUREBLENDMODE_BLEND:

            data->glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);

            data->glEnable(GL_BLEND);

            data->glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

            break;

        case SDL_TEXTUREBLENDMODE_ADD:

            data->glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);

            data->glEnable(GL_BLEND);

            data->glBlendFunc(GL_SRC_ALPHA, GL_ONE);

            break;

        case SDL_TEXTUREBLENDMODE_MOD:

            data->glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);

            data->glEnable(GL_BLEND);

            data->glBlendFunc(GL_ZERO, GL_SRC_COLOR);

            break;

        }

        data->blendMode = texture->blendMode;

    }

	switch (texture->scaleMode) {

		case SDL_TEXTURESCALEMODE_NONE:

		case SDL_TEXTURESCALEMODE_FAST:

			data->glTexParameteri(texturedata->type, GL_TEXTURE_MIN_FILTER,

								  GL_NEAREST);

			data->glTexParameteri(texturedata->type, GL_TEXTURE_MAG_FILTER,

								  GL_NEAREST);

			break;

		case SDL_TEXTURESCALEMODE_SLOW:

		case SDL_TEXTURESCALEMODE_BEST:

			data->glTexParameteri(texturedata->type, GL_TEXTURE_MIN_FILTER,

								  GL_LINEAR);

			data->glTexParameteri(texturedata->type, GL_TEXTURE_MAG_FILTER,

								  GL_LINEAR);

			break;

	}

	if (data->GL_OES_draw_texture_supported && data->useDrawTexture) {

		/* this code is a little funny because the viewport is upside down vs SDL's coordinate system */

		SDL_Window *window = SDL_GetWindowFromID(renderer->window);

		GLint cropRect[4];

		cropRect[0] = srcrect->x;

		cropRect[1] = srcrect->y + srcrect->h;

		cropRect[2] = srcrect->w;

		cropRect[3] = -srcrect->h;

		data->glTexParameteriv(GL_TEXTURE_2D, GL_TEXTURE_CROP_RECT_OES, cropRect);

		data->glDrawTexiOES(dstrect->x, window->h - dstrect->y - dstrect->h, 0, dstrect->w, dstrect->h);

	}

	else {

		minx = dstrect->x;

		miny = dstrect->y;

		maxx = dstrect->x + dstrect->w;

		maxy = dstrect->y + dstrect->h;

		minu = (GLfloat) srcrect->x / texture->w;

		minu *= texturedata->texw;

		maxu = (GLfloat) (srcrect->x + srcrect->w) / texture->w;

		maxu *= texturedata->texw;

		minv = (GLfloat) srcrect->y / texture->h;

		minv *= texturedata->texh;

		maxv = (GLfloat) (srcrect->y + srcrect->h) / texture->h;

		maxv *= texturedata->texh;			

		GLshort vertices[8];

		GLfloat texCoords[8];

		vertices[0] = minx; vertices[1] = miny;

		vertices[2] = maxx; vertices[3] = miny;

		vertices[4]	= minx; vertices[5] = maxy;

		vertices[6] = maxx; vertices[7] = maxy;	

		texCoords[0] = minu; texCoords[1] = minv;

		texCoords[2] = maxu; texCoords[3] = minv;

		texCoords[4] = minu; texCoords[5] = maxv;

		texCoords[6] = maxu; texCoords[7] = maxv;	

		data->glVertexPointer(2, GL_SHORT, 0, vertices);

		data->glEnableClientState(GL_VERTEX_ARRAY);

		data->glTexCoordPointer(2, GL_FLOAT, 0, texCoords);

		data->glEnableClientState(GL_TEXTURE_COORD_ARRAY);

		data->glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

	}

    return 0;

}

static void

GLES_RenderPresent(SDL_Renderer * renderer)

{

    SDL_GL_SwapWindow(renderer->window);

}

static void

GLES_DestroyTexture(SDL_Renderer * renderer, SDL_Texture * texture)

{

    GLES_RenderData *renderdata = (GLES_RenderData *) renderer->driverdata;

    GLES_TextureData *data = (GLES_TextureData *) texture->driverdata;

    if (!data) {

        return;

    }

    if (data->texture) {

		glDeleteTextures(1, &data->texture);

    }

    if (data->pixels) {

        SDL_free(data->pixels);

    }

    SDL_FreeDirtyRects(&data->dirty);

    SDL_free(data);

    texture->driverdata = NULL;

}

static void

GLES_DestroyRenderer(SDL_Renderer * renderer)

{

    GLES_RenderData *data = (GLES_RenderData *) renderer->driverdata;

    if (data) {

        if (data->context) {

            /* SDL_GL_MakeCurrent(0, NULL); *//* doesn't do anything */

            SDL_GL_DeleteContext(data->context);

        }

        SDL_free(data);

    }

    SDL_free(renderer);

}

#endif /* SDL_VIDEO_RENDER_OGL */

/* vi: set ts=4 sw=4 expandtab: */