/*

    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_ES

#include "SDL_opengles.h"

#include "../SDL_sysrender.h"

#if defined(SDL_VIDEO_DRIVER_PANDORA)

/* Empty function stub to get OpenGL ES 1.x support without  */

/* OpenGL ES extension GL_OES_draw_texture supported         */

GL_API void GL_APIENTRY

glDrawTexiOES(GLint x, GLint y, GLint z, GLint width, GLint height)

{

    return;

}

#endif /* PANDORA */

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

/* Used to re-create the window with OpenGL capability */

extern int SDL_RecreateWindow(SDL_Window * window, Uint32 flags);

static const float inv255f = 1.0f / 255.0f;

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

static void GLES_WindowEvent(SDL_Renderer * renderer,

                             const SDL_WindowEvent *event);

static int GLES_CreateTexture(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, void **pixels, int *pitch);

static void GLES_UnlockTexture(SDL_Renderer * renderer,

                               SDL_Texture * texture);

static int GLES_RenderDrawPoints(SDL_Renderer * renderer,

                                 const SDL_Point * points, int count);

static int GLES_RenderDrawLines(SDL_Renderer * renderer,

                                const SDL_Point * points, int count);

static int GLES_RenderFillRects(SDL_Renderer * renderer,

                                const SDL_Rect ** rects, int count);

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 GLES_RenderDriver = {

    GLES_CreateRenderer,

    {

     "opengles",

     (SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC),

     1,

     {SDL_PIXELFORMAT_ABGR8888},

     0,

     0}

};

typedef struct

{

    SDL_GLContext context;

    SDL_bool updateSize;

    int blendMode;

    SDL_bool useDrawTexture;

    SDL_bool GL_OES_draw_texture_supported;

} GLES_RenderData;

typedef struct

{

    GLuint texture;

    GLenum type;

    GLfloat texw;

    GLfloat texh;

    GLenum format;

    GLenum formattype;

    void *pixels;

    int pitch;

} 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);

}

SDL_Renderer *

GLES_CreateRenderer(SDL_Window * window, Uint32 flags)

{

    SDL_Renderer *renderer;

    GLES_RenderData *data;

    GLint value;

    Uint32 window_flags;

    window_flags = SDL_GetWindowFlags(window);

    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->WindowEvent = GLES_WindowEvent;

    renderer->CreateTexture = GLES_CreateTexture;

    renderer->UpdateTexture = GLES_UpdateTexture;

    renderer->LockTexture = GLES_LockTexture;

    renderer->UnlockTexture = GLES_UnlockTexture;

    renderer->RenderDrawPoints = GLES_RenderDrawPoints;

    renderer->RenderDrawLines = GLES_RenderDrawLines;

    renderer->RenderFillRects = GLES_RenderFillRects;

    renderer->RenderCopy = GLES_RenderCopy;

    renderer->RenderPresent = GLES_RenderPresent;

    renderer->DestroyTexture = GLES_DestroyTexture;

    renderer->DestroyRenderer = GLES_DestroyRenderer;

    renderer->info = GLES_RenderDriver.info;

    renderer->driverdata = data;

    renderer->info.flags = SDL_RENDERER_ACCELERATED;

    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 1);

    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 1);

    data->context = SDL_GL_CreateContext(window);

    if (!data->context) {

        GLES_DestroyRenderer(renderer);

        return NULL;

    }

    if (SDL_GL_MakeCurrent(window, 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_VIDEO_DRIVER_PANDORA

    data->GL_OES_draw_texture_supported = SDL_FALSE;

    data->useDrawTexture = SDL_FALSE;

#else

    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;

    }

#endif

    glGetIntegerv(GL_MAX_TEXTURE_SIZE, &value);

    renderer->info.max_texture_width = value;

    glGetIntegerv(GL_MAX_TEXTURE_SIZE, &value);

    renderer->info.max_texture_height = value;

    /* Set up parameters for rendering */

    data->blendMode = -1;

    glDisable(GL_DEPTH_TEST);

    glDisable(GL_CULL_FACE);

    data->updateSize = SDL_TRUE;

    glEnableClientState(GL_VERTEX_ARRAY);

    glEnableClientState(GL_TEXTURE_COORD_ARRAY);

    return renderer;

}

static SDL_GLContext SDL_CurrentContext = NULL;

static int

GLES_ActivateRenderer(SDL_Renderer * renderer)

{

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

    SDL_Window *window = renderer->window;

    if (SDL_CurrentContext != data->context) {

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

            return -1;

        }

        SDL_CurrentContext = data->context;

    }

    if (data->updateSize) {

        int w, h;

        SDL_GetWindowSize(window, &w, &h);

        glMatrixMode(GL_PROJECTION);

        glLoadIdentity();

        glMatrixMode(GL_MODELVIEW);

        glLoadIdentity();

        glViewport(0, 0, w, h);

        glOrthof(0.0, (GLfloat) w, (GLfloat) h, 0.0, 0.0, 1.0);

        data->updateSize = SDL_FALSE;

    }

    return 0;

}

static void

GLES_WindowEvent(SDL_Renderer * renderer, const SDL_WindowEvent *event)

{

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

    if (event->event == SDL_WINDOWEVENT_RESIZED) {

        /* Rebind the context to the window area and update matrices */

        SDL_CurrentContext = NULL;

        data->updateSize = SDL_TRUE;

    }

}

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;

    GLES_TextureData *data;

    GLint internalFormat;

    GLenum format, type;

    int texture_w, texture_h;

    GLenum result;

    GLES_ActivateRenderer(renderer);

    switch (texture->format) {

    case SDL_PIXELFORMAT_ABGR8888:

        internalFormat = GL_RGBA;

        format = GL_RGBA;

        type = GL_UNSIGNED_BYTE;

        break;

    default:

        SDL_SetError("Texture format not supported");

        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;

    glGetError();

    glEnable(GL_TEXTURE_2D);

    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;

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

    glTexParameteri(data->type, GL_TEXTURE_MIN_FILTER,

                                GL_LINEAR);

    glTexParameteri(data->type, GL_TEXTURE_MAG_FILTER,

                                GL_LINEAR);

    glTexParameteri(data->type, GL_TEXTURE_WRAP_S,

                                GL_CLAMP_TO_EDGE);

    glTexParameteri(data->type, GL_TEXTURE_WRAP_T,

                                GL_CLAMP_TO_EDGE);

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

                             texture_h, 0, format, type, NULL);

    glDisable(GL_TEXTURE_2D);

    result = glGetError();

    if (result != GL_NO_ERROR) {

        GLES_SetError("glTexImage2D()", result);

        return -1;

    }

    return 0;

}

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;

    int bpp = SDL_BYTESPERPIXEL(texture->format);

    void * temp_buffer;

    void * temp_ptr;

    int i;

    GLES_ActivateRenderer(renderer);

    glGetError();

    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);

    glEnable(data->type);

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

    if( rect->w * bpp == pitch ) {

         temp_buffer = (void *)pixels; /* No need to reformat */

    } else {

         /* Reformatting of mem area required */

         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;

         }

    }

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

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

                                temp_buffer);

    if( temp_buffer != pixels ) {

        SDL_free(temp_buffer);

    }

    glDisable(data->type);

    result = 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, void **pixels, int *pitch)

{

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

    *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)

{

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

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

    GLES_ActivateRenderer(renderer);

    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);

    glEnable(data->type);

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

    glTexSubImage2D(data->type, 0, 0, 0, texture->w,

                                texture->h, data->format, data->formattype,

                                data->pixels);

    glDisable(data->type);

}

static void

GLES_SetBlendMode(GLES_RenderData * data, int blendMode)

{

    if (blendMode != data->blendMode) {

        switch (blendMode) {

        case SDL_BLENDMODE_NONE:

            glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);

            glDisable(GL_BLEND);

            break;

        case SDL_BLENDMODE_BLEND:

            glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);

            glEnable(GL_BLEND);

            glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

            break;

        case SDL_BLENDMODE_ADD:

            glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);

            glEnable(GL_BLEND);

            glBlendFunc(GL_SRC_ALPHA, GL_ONE);

            break;

        case SDL_BLENDMODE_MOD:

            glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);

            glEnable(GL_BLEND);

            glBlendFunc(GL_ZERO, GL_SRC_COLOR);

            break;

        }

        data->blendMode = blendMode;

    }

}

static int

GLES_RenderDrawPoints(SDL_Renderer * renderer, const SDL_Point * points,

                      int count)

{

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

    int i;

    GLshort *vertices;

    GLES_ActivateRenderer(renderer);