/*
* SDLEMU library - Free sdl related functions library
- * Copyrigh(c) 1999-2002 sdlemu development crew
+ * Copyrigh(c) 1999-2004 sdlemu development crew
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
+/* SDLEMU_OPENGL.C
+ SDLEMU related sources for using OpenGL with SDL.
+ By Niels Wagenaar | http://sdlemu.ngemu.com | shalafi@xs4all.nl
+
+ Version 1.0.001 - 4-10-2004
+
+ - Added support for 16, 24 and 32 bit textures;
+ - Added support for 16, 24 and 32 bit texture rendering;
+
+ Version 1.0.002 - 6-10-2004
+
+ - Cleaned up a lot of code and removed non functional and obsolete code;
+ - Removed sdlemu_resize_texture function because of double code;
+ - Removed the texture creation from the sdlemu_init_opengl;
+ - Added sdlemu_create_texture function to replace the sdlemu_resize_texture function
+ and the texture creation in sdlemu_init_opengl;
+ - Added the usage of OPENGL_16BPP_CORRECT_RGBA for activating the correct 16bpp RGBA masks;
+ - Added the usage of WANT_OPENGL_ALPHA for using ALPHA blending with 32bpp textures;
+ - Added automatic and override texture bpp depth setting (based upon the src surface);
+
+*/
+
#include "sdlemu_opengl.h"
+// We want alpha on our OpenGL contexts...!
+// Or do we? Seems to kill performance on X...
+// Or does it? Could it be bad blitter performance?
+#define WANT_OPENGL_ALPHA
+
static SDL_Surface *texture = 0;
static GLuint texid = 0;
static GLfloat texcoord[4];
static unsigned int glFilter;
+static unsigned int texturebpp = 0; // 16, 24 or 32 bpp
+
+static SDL_Surface * overlay = 0;
+static GLuint overlayID = 0;
+static GLfloat overlayCoord[4];
+void sdlemu_create_overlay(SDL_Surface * dst, int src_bpp);
+
+static int showOverlay = 0;
static inline int power_of_two(int input)
{
return value;
}
-void sdlemu_init_opengl(SDL_Surface * src, int texturetype, float size, int filter)
+void sdlemu_init_opengl(SDL_Surface * src, SDL_Surface * dst, int texturetype, int filter, int src_bpp)
{
- int w, h;
-
printf("\nOpenGL driver information :\n");
printf("\n");
- printf("Vendor: %s\n", glGetString(GL_VENDOR));
- printf("Renderer: %s\n", glGetString(GL_RENDERER));
- printf("Version: %s\n", glGetString(GL_VERSION));
+ printf("Vendor: %s\n", glGetString(GL_VENDOR));
+ printf("Renderer: %s\n", glGetString(GL_RENDERER));
+ printf("Version: %s\n", glGetString(GL_VERSION));
printf("OpenGL drawmethod: ");
switch (texturetype)
glFilter = filter;
- // Texture width/height should be power of 2
- // So, find the largest power of two that will contain both the width and height
- w = power_of_two(src->w);
- h = power_of_two(src->h);
-
- // create texture surface
- texture = SDL_CreateRGBSurface(SDL_SWSURFACE, w, h, 32,
- #if SDL_BYTEORDER == SDL_LIL_ENDIAN
- 0x000000FF, 0x0000FF00, 0x00FF0000, 0xFF000000);
- #else
- 0xFF000000, 0x00FF0000, 0x0000FF00, 0x000000FF);
- #endif
-
- // setup 2D gl environment
- glPushAttrib(GL_ENABLE_BIT);
- glDisable(GL_DEPTH_TEST);
- glDisable(GL_CULL_FACE);
- glEnable(GL_TEXTURE_2D);
-
- glViewport(0, 0, src->w * size, src->h * size);
-
- glMatrixMode(GL_PROJECTION);
- glPushMatrix();
- glLoadIdentity();
-
- glOrtho(0.0, (GLdouble)(src->w * size), (GLdouble)(src->h * size), 0.0, 0.0, 1.0);
- glMatrixMode(GL_MODELVIEW);
- glPushMatrix();
- glLoadIdentity();
-
- // texture coordinates
- texcoord[0] = 0.0f;
- texcoord[1] = 0.0f;
- texcoord[2] = (GLfloat)(src->w) / texture->w;
- texcoord[3] = (GLfloat)(src->h) / texture->h;
-
- // create an RGBA texture for the texture surface
- glGenTextures(1, &texid);
- glBindTexture(GL_TEXTURE_2D, texid);
-
- if (glFilter)
- {
- printf("OpenGL filters: enabled\n");
- glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
- glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
- }
- else
- {
- printf("OpenGL filters: disabled\n");
- glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
- glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
- }
-
- glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, texture->w, texture->h, 0, GL_RGBA, GL_UNSIGNED_BYTE, texture->pixels);
+ // Let us create the texture information :
+ sdlemu_create_texture(src, dst, filter, src_bpp);
+ sdlemu_create_overlay(dst, src_bpp);
}
void sdlemu_draw_texture(SDL_Surface * dst, SDL_Surface * src, int texturetype)
{
+/*
+ This is needed when we want to render OpenGL textures with the Alpha mask set.
+ Be warned! This only works with the bpp of texture en *src set to 32.
+*/
+#ifdef WANT_OPENGL_ALPHA
+ Uint32 saved_flags;
+ Uint8 saved_alpha;
+
+ /* Save the alpha blending attributes */
+ saved_flags = src->flags&(SDL_SRCALPHA|SDL_RLEACCELOK);
+ saved_alpha = src->format->alpha;
+ if ( (saved_flags & SDL_SRCALPHA) == SDL_SRCALPHA ) {
+ SDL_SetAlpha(src, 0, 0);
+ }
+
+ // Blit the src display to the texture.
+ SDL_BlitSurface(src, NULL, texture, NULL);
- // convert color-indexed surface to RGB texture
+ /* Restore the alpha blending attributes */
+ if ( (saved_flags & SDL_SRCALPHA) == SDL_SRCALPHA ) {
+ SDL_SetAlpha(src, saved_flags, saved_alpha);
+ }
+#else
SDL_BlitSurface(src, NULL, texture, NULL);
+#endif
+// SDL_BlitSurface(src, NULL, overlay, NULL);
+/*Uint32 * pix = (Uint32 *)overlay->pixels;
+Uint32 y,x;
+for(y=10; y<200; y++)
+for(x=30; x<250; x++)
+pix[x+(y*1024)] = 0x800000FF;//*/
+
+glBlendFunc(GL_ONE, GL_ZERO);
+glBindTexture(GL_TEXTURE_2D, texid);
+ // Texturemap complete texture to surface so we have free scaling
+ // and antialiasing
+ switch (texturebpp)
+ {
+ case 16:
+ glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, texture->w, texture->h,
+ GL_RGB, GL_UNSIGNED_SHORT_5_6_5, texture->pixels);
+ break;
+ case 24:
+ glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, texture->w, texture->h,
+ GL_RGB, GL_UNSIGNED_BYTE, texture->pixels);
+ break;
+ case 32:
+ default:
+ glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, texture->w, texture->h,
+ GL_RGBA, GL_UNSIGNED_BYTE, texture->pixels);
+ break;
+ }
- // Texturemap complete texture to surface so we have free scaling
- // and antialiasing
- glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, texture->w, texture->h,
- GL_RGBA, GL_UNSIGNED_BYTE, texture->pixels);
-
+ // Render the texture to the screen using OpenGL!
switch (texturetype)
{
case 1:
- glBegin(GL_QUADS);
- glTexCoord2f(texcoord[0], texcoord[1]);
- glVertex2f(0, 0);
- glTexCoord2f(texcoord[2], texcoord[1]);
- glVertex2f(dst->w , 0);
- glTexCoord2f(texcoord[2], texcoord[3]);
- glVertex2f(dst->w , dst->h );
- glTexCoord2f(texcoord[0], texcoord[3]);
- glVertex2f(0, dst->h );
- glEnd();
+ glBegin(GL_QUADS);
+ glTexCoord2f(texcoord[0], texcoord[1]);
+ glVertex2f(0, 0);
+ glTexCoord2f(texcoord[2], texcoord[1]);
+ glVertex2f(dst->w, 0);
+ glTexCoord2f(texcoord[2], texcoord[3]);
+ glVertex2f(dst->w, dst->h);
+ glTexCoord2f(texcoord[0], texcoord[3]);
+ glVertex2f(0, dst->h);
+ glEnd();
default:
glBegin(GL_TRIANGLE_STRIP);
- glTexCoord2f(texcoord[0], texcoord[1]); glVertex3i(0, 0, 0);
- glTexCoord2f(texcoord[2], texcoord[1]); glVertex3i(dst->w, 0, 0);
- glTexCoord2f(texcoord[0], texcoord[3]); glVertex3i(0, dst->h, 0);
- glTexCoord2f(texcoord[2], texcoord[3]); glVertex3i(dst->w, dst->h, 0);
+ glTexCoord2f(texcoord[0], texcoord[1]); glVertex3i(0, 0, 0);
+ glTexCoord2f(texcoord[2], texcoord[1]); glVertex3i(dst->w, 0, 0);
+ glTexCoord2f(texcoord[0], texcoord[3]); glVertex3i(0, dst->h, 0);
+ glTexCoord2f(texcoord[2], texcoord[3]); glVertex3i(dst->w, dst->h, 0);
+ glEnd();
+ }//*/
+
+ if (showOverlay)
+ {
+ glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+ glBindTexture(GL_TEXTURE_2D, overlayID);
+ glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, overlay->w, overlay->h, GL_RGBA, GL_UNSIGNED_BYTE, overlay->pixels);
+ glBegin(GL_QUADS);
+ glTexCoord2f(overlayCoord[0], overlayCoord[1]);
+ glVertex2f(0, 0);
+ glTexCoord2f(overlayCoord[2], overlayCoord[1]);
+ glVertex2f(dst->w, 0);
+ glTexCoord2f(overlayCoord[2], overlayCoord[3]);
+ glVertex2f(dst->w, dst->h);
+ glTexCoord2f(overlayCoord[0], overlayCoord[3]);
+ glVertex2f(0, dst->h);
glEnd();
}
- SDL_GL_SwapBuffers();
+//Do some OpenGL stuff here...
+//Doesn't work...
+/*unsigned long int map[25] = {
+ 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF,
+ 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF,
+ 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF,
+ 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF,
+ 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF
+};
+glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+glRasterPos2i(10, 10);
+glDrawPixels(5, 5, GL_RGBA, GL_UNSIGNED_INT, map);//*/
+
+// glFlush();
+ SDL_GL_SwapBuffers();
+// glFinish();
+
}
void sdlemu_close_opengl(void)
{
if (texture)
SDL_FreeSurface(texture);
-}
+ if (overlay)
+ SDL_FreeSurface(overlay);
+}
-//
-// Resize the texture
-// This should honor the glFilter flag that is passed in to the initialization code,
-// but, at the moment, it doesn't...
-// Now it does...!
-//
-void sdlemu_resize_texture(SDL_Surface * src, SDL_Surface * dst, int filter)
+void sdlemu_create_overlay(SDL_Surface * dst, int src_bpp)
{
- // Texture width/height should be power of 2
+ // Local variables.
+ Uint32 rmask, gmask, bmask, amask; // Needed for creating RGBA masks.
+
+ // Delete old texture (if allocated). Useful when there is a screen resize.
+ if (overlay)
+ SDL_FreeSurface(overlay);
+
+ // Texture width/height should be power of 2 of the SDL_Surface *src when using OpenGL.
// So, find the largest power of two that will contain both the width and height
- int w = power_of_two(src->w), h = power_of_two(src->h);
+ int w = power_of_two(dst->w);
+ int h = power_of_two(dst->h);
+
+ printf("OpenGL - Overlay size : %d x %d\n", w, h);
+
+ // Setting bpp based upon src_bpp.
+ int bpp = src_bpp;
- // Delete old texture (if allocated)
+ // We allow the developer to set its own texture bpp. But if the value is NULL or
+ // not equal to 16, 24 or 32, we make the texturebpp the same as the BPP from src.
+ if (bpp == 16 || bpp == 24 || bpp == 32)
+ texturebpp = bpp;
+ else
+ texturebpp = dst->format->BitsPerPixel;
+
+ printf("OpenGL - Overlay depth : %d bpp\n", texturebpp);
+
+ // Now were are going to create a SDL_Surface named texture. This will be our surface
+ // which will function as a buffer between the SDL_Surface *src and SDL_Surface *dst.
+ // This buffer is needed because we need to convert the SDL_Surface *src to an OpenGL
+ // texture with a depth of 16, 24 or 32 bpp, before we can blit the pixels to *dst
+ // using OpenGL.
+ //
+ // NOTE: Seems the byte order here *is* important!
+ switch (texturebpp)
+ {
+ case 16: // *src has depth of 16 bpp
+/*
+ According to information on the SDL mailinglist and on internet, the following
+ rgba masks should be the ones to use. But somehow the screen gets f*cked up and
+ the RGB colours are incorrect (at least in Virtual Jaguar/SDL).
+
+ Compile with -DOPENGL_16BPP_CORRECT_RGBA to use this RGBA values.
+*/
+#ifdef OPENGL_16BPP_CORRECT_RGBA
+ rmask = 0x7C00;
+ gmask = 0x03E0;
+ bmask = 0x001F;
+ amask = 0x0000;
+#else
+ rmask = 0x0000;
+ gmask = 0x0000;
+ bmask = 0x0000;
+ amask = 0x0000;
+#endif
+ break;
+ case 24: // *src has depth of 24 bpp
+ #if SDL_BYTEORDER == SDL_BIG_ENDIAN
+ rmask = 0x00FF0000;
+ gmask = 0x0000FF00;
+ bmask = 0x000000FF;
+ amask = 0x00000000; // IMPORTANT! 24 bpp doesn't use Alpha (at least in our case).
+ #else
+ rmask = 0x000000FF;
+ gmask = 0x0000FF00;
+ bmask = 0x00FF0000;
+ amask = 0x00000000; // IMPORTANT! 24 bpp doesn't use Alpha (at least in our case).
+ #endif
+ break;
+ case 32: //*src has depth of 32 bpp
+ default: //which is also the default.
+ #if SDL_BYTEORDER == SDL_BIG_ENDIAN
+ rmask = 0xFF000000;
+ gmask = 0x00FF0000;
+ bmask = 0x0000FF00;
+ amask = 0x000000FF;
+ #else
+ rmask = 0x000000FF;
+ gmask = 0x0000FF00;
+ bmask = 0x00FF0000;
+ amask = 0xFF000000;
+ #endif
+ break;
+ }
+
+ // Creating SDL_Surface texture based upon the above settings.
+ overlay = SDL_CreateRGBSurface(SDL_SWSURFACE, w, h, texturebpp, rmask, gmask, bmask, amask);
+
+ // Setting up the texture coordinates.
+ overlayCoord[0] = 0.0f;
+ overlayCoord[1] = 0.0f;
+ overlayCoord[2] = (GLfloat)(dst->w) / overlay->w;
+ overlayCoord[3] = (GLfloat)(dst->h) / overlay->h;
+
+ // create a RGB(A) texture for the texture surface
+ glGenTextures(1, &overlayID);
+ glBindTexture(GL_TEXTURE_2D, overlayID);
+
+ glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+ glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+
+ // Setting texture mode.
+ glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
+ glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
+
+ // Generate the texture using the above information.
+ switch (texturebpp)
+ {
+ case 16:
+ // Normal 16bpp depth based textures consist out of GL_RGB5 and doesn't have support for Alpha channels.
+ glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB5, overlay->w, overlay->h, 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);
+ break;
+ case 24:
+ // The 24bpp depth based textures consist out of GL_RGB8 and doesn't have support for Alpha channels.
+ //
+ // IMPORTANT : If you don't use Alpha. Use textures with a depth of 16bpp.
+ // If you use Alpha. Use textures with a depth of 32bpp.
+ // 24bpp textures are SLOW and avoid them at all costs!
+ glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB8, overlay->w, overlay->h, 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);
+ break;
+ case 32:
+ default:
+ // The 32bpp depth based textures consist out of GL_RGBA8 and has support for Alpha channels.
+ glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, overlay->w, overlay->h, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
+ break;
+ }
+}
+
+void * sdlemuGetOverlayPixels(void)
+{
+ return overlay->pixels;
+}
+
+Uint32 sdlemuGetOverlayWidthInPixels(void)
+{
+ return overlay->pitch / 4;
+}
+
+void sdlemuEnableOverlay(void)
+{
+ showOverlay = 1;
+}
+
+void sdlemuDisableOverlay(void)
+{
+ showOverlay = 0;
+}
+
+void sdlemu_create_texture(SDL_Surface * src, SDL_Surface * dst, int filter, int src_bpp)
+{
+ // Local variables.
+ int w , h; // w and h contain the width and height of the OpenGL texture.
+ Uint32 rmask, gmask, bmask, amask; // Needed for creating RGBA masks.
+ int bpp;
+
+ // Delete old texture (if allocated). Useful when there is a screen resize.
if (texture)
SDL_FreeSurface(texture);
- // create texture surface
-//NOTE: Seems the byte order here *is* important! (Perhaps only for 32 BPP?)
- texture = SDL_CreateRGBSurface(SDL_SWSURFACE, w, h, 32,
- #if SDL_BYTEORDER == SDL_LIL_ENDIAN
- 0x000000FF, 0x0000FF00, 0x00FF0000, 0xFF000000);
+ // Texture width/height should be power of 2 of the SDL_Surface *src when using OpenGL.
+ // So, find the largest power of two that will contain both the width and height
+ w = power_of_two(src->w);
+ h = power_of_two(src->h);
+
+ printf("OpenGL - Texture size : %d x %d\n", w, h);
+
+ // Setting bpp based upon src_bpp.
+ bpp = src_bpp;
+
+ // We allow the developer to set its own texture bpp. But if the value is NULL or
+ // not equal to 16, 24 or 32, we make the texturebpp the same as the BPP from src.
+ if (bpp == 16 || bpp == 24 || bpp == 32)
+ texturebpp = bpp;
+ else
+ texturebpp = src->format->BitsPerPixel;
+
+ printf("OpenGL - Texture depth : %d bpp\n", texturebpp);
+
+ // Now were are going to create a SDL_Surface named texture. This will be our surface
+ // which will function as a buffer between the SDL_Surface *src and SDL_Surface *dst.
+ // This buffer is needed because we need to convert the SDL_Surface *src to an OpenGL
+ // texture with a depth of 16, 24 or 32 bpp, before we can blit the pixels to *dst
+ // using OpenGL.
+ //
+ // NOTE: Seems the byte order here *is* important!
+ switch (texturebpp)
+ {
+ case 16: // *src has depth of 16 bpp
+/*
+ According to information on the SDL mailinglist and on internet, the following
+ rgba masks should be the ones to use. But somehow the screen gets f*cked up and
+ the RGB colours are incorrect (at least in Virtual Jaguar/SDL).
+
+ Compile with -DOPENGL_16BPP_CORRECT_RGBA to use this RGBA values.
+*/
+#ifdef OPENGL_16BPP_CORRECT_RGBA
+ rmask = 0x7C00;
+ gmask = 0x03E0;
+ bmask = 0x001F;
+ amask = 0x0000;
+#else
+ rmask = 0x0000;
+ gmask = 0x0000;
+ bmask = 0x0000;
+ amask = 0x0000;
+#endif
+ break;
+ case 24: // *src has depth of 24 bpp
+ #if SDL_BYTEORDER == SDL_BIG_ENDIAN
+ rmask = 0x00FF0000;
+ gmask = 0x0000FF00;
+ bmask = 0x000000FF;
+ amask = 0x00000000; // IMPORTANT! 24 bpp doesn't use Alpha (at least in our case).
+ #else
+ rmask = 0x000000FF;
+ gmask = 0x0000FF00;
+ bmask = 0x00FF0000;
+ amask = 0x00000000; // IMPORTANT! 24 bpp doesn't use Alpha (at least in our case).
+ #endif
+ break;
+ case 32: //*src has depth of 32 bpp
+ default: //which is also the default.
+ #if SDL_BYTEORDER == SDL_BIG_ENDIAN
+ rmask = 0xFF000000;
+ gmask = 0x00FF0000;
+ bmask = 0x0000FF00;
+ amask = 0x000000FF;
#else
- 0xFF000000, 0x00FF0000, 0x0000FF00, 0x000000FF);
+ rmask = 0x000000FF;
+ gmask = 0x0000FF00;
+ bmask = 0x00FF0000;
+ amask = 0xFF000000;
#endif
+ break;
+ }
- // setup 2D gl environment
- glPushAttrib(GL_ENABLE_BIT);
- glDisable(GL_DEPTH_TEST);
+ // Creating SDL_Surface texture based upon the above settings.
+ texture = SDL_CreateRGBSurface(SDL_SWSURFACE, w, h, texturebpp, rmask, gmask, bmask, amask);
+
+ // Setting up OpenGL
+ glDisable(GL_FOG);
+ glDisable(GL_LIGHTING);
glDisable(GL_CULL_FACE);
+ glDisable(GL_DEPTH_TEST);
+// glDisable(GL_BLEND);
+ glEnable(GL_BLEND);
+ glDisable(GL_NORMALIZE);
+ glDisable(GL_ALPHA_TEST);
glEnable(GL_TEXTURE_2D);
+// glBlendFunc(GL_SRC_ALPHA, GL_ONE);
+// glBlendFunc(GL_ONE, GL_SRC_ALPHA);
+//This works, but in a wrong way...
+// glBlendFunc(GL_ONE, GL_ONE);
+ // Definitely needed for screen resolution larger then the *src.
+ // This way we can have automatic scaling functionality.
glViewport(0, 0, dst->w, dst->h);
-
glMatrixMode(GL_PROJECTION);
glPushMatrix();
glLoadIdentity();
-
glOrtho(0.0, (GLdouble)dst->w, (GLdouble)dst->h, 0.0, 0.0, 1.0);
glMatrixMode(GL_MODELVIEW);
glPushMatrix();
glLoadIdentity();
- // texture coordinates
- texcoord[0] = 0.0f, texcoord[1] = 0.0f,
- texcoord[2] = (GLfloat)(src->w) / texture->w,
+ // Setting up the texture coordinates.
+ texcoord[0] = 0.0f;
+ texcoord[1] = 0.0f;
+ texcoord[2] = (GLfloat)(src->w) / texture->w;
texcoord[3] = (GLfloat)(src->h) / texture->h;
- // create an RGBA texture for the texture surface
+ // create a RGB(A) texture for the texture surface
glGenTextures(1, &texid);
glBindTexture(GL_TEXTURE_2D, texid);
-
-// if (glFilter)
+
+ // Setting up the OpenGL Filters. These filters are important when we/you
+ // want to scale the texture.
if (filter)
{
- printf("OpenGL filters: enabled\n");
- glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
- glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+ // Textures are rendered in best quality.
+ printf("OpenGL filters: enabled\n");
+ glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+ glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
}
else
{
- printf("OpenGL filters: disabled\n");
- glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
- glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
- }
+ // Textures are rendered in normal quality.
+ printf("OpenGL filters: disabled\n");
+ glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+ glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+ }
+
+ // Setting texture mode.
+ glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
+ glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
- glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, texture->w, texture->h, 0, GL_RGBA, GL_UNSIGNED_BYTE, texture->pixels);
+ // Generate the texture using the above information.
+ switch (texturebpp)
+ {
+ case 16:
+ // Normal 16bpp depth based textures consist out of GL_RGB5 and doesn't have support for Alpha channels.
+ glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB5, texture->w, texture->h, 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);
+ break;
+ case 24:
+ // The 24bpp depth based textures consist out of GL_RGB8 and doesn't have support for Alpha channels.
+ //
+ // IMPORTANT : If you don't use Alpha. Use textures with a depth of 16bpp.
+ // If you use Alpha. Use textures with a depth of 32bpp.
+ // 24bpp textures are SLOW and avoid them at all costs!
+ glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB8, texture->w, texture->h, 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);
+ break;
+ case 32:
+ default:
+ // The 32bpp depth based textures consist out of GL_RGBA8 and has support for Alpha channels.
+ glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, texture->w, texture->h, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
+ break;
+ }
}
projects / virtualjaguar / blobdiff