demos: update fbotexture.c to use EXT or ARB functions exclusively

When the -arb option is specified we use GL_ARB_framebuffer_object intead
of GL_EXT_framebuffer_object.

For some vendors' OpenGL it's important to call the ARB entrypoints
instead of the EXT entrypoints to get correct behaviour.  Use some
function pointer tricks to do this (instead of GLEW).

2 files changed, 77 insertions, 38 deletions

diff --git a/progs/demos/Makefile b/progs/demos/Makefile
index c17595ec794..65fdbaaad8e 100644
--- a/progs/demos/Makefile
+++ b/progs/demos/Makefile
@@ -145,6 +145,13 @@ engine.o: engine.c trackball.h
 	$(APP_CC) -c -I$(INCDIR) $(CFLAGS) engine.c
 
 
+fbotexture: fbotexture.o
+	$(APP_CC) $(CFLAGS) $(LDFLAGS) fbotexture.o $(LIBS) -o $@
+
+fbotexture.o: fbotexture.c extfuncs.h
+	$(APP_CC) -c -I$(INCDIR) $(CFLAGS) fbotexture.c
+
+
 fslight: fslight.o
 	$(APP_CC) $(CFLAGS) $(LDFLAGS) fslight.o $(LIBS) -o $@
 
diff --git a/progs/demos/fbotexture.c b/progs/demos/fbotexture.c
index 50a4b00afce..3b36f755a04 100644
--- a/progs/demos/fbotexture.c
+++ b/progs/demos/fbotexture.c
@@ -9,13 +9,13 @@
  */
 
 
-#include <GL/glew.h>
 #include <GL/glut.h>
 #include <assert.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <math.h>
+#include "extfuncs.h"
 
 /* For debug */
 #define DEPTH 1
@@ -80,9 +80,9 @@ RenderTexture(void)
    glTranslatef(0.0, 0.0, -15.0);
 
    /* draw to texture image */
-   glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, MyFB);
+   glBindFramebuffer_func(GL_FRAMEBUFFER_EXT, MyFB);
 
-   status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
+   status = glCheckFramebufferStatus_func(GL_FRAMEBUFFER_EXT);
    if (status != GL_FRAMEBUFFER_COMPLETE_EXT) {
       printf("Framebuffer incomplete!!!\n");
    }
@@ -171,7 +171,7 @@ RenderTexture(void)
 
 #if DRAW
    /* Bind normal framebuffer */
-   glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
+   glBindFramebuffer_func(GL_FRAMEBUFFER_EXT, 0);
 #endif
 
    CheckError(__LINE__);
@@ -252,12 +252,12 @@ static void
 CleanUp(void)
 {
 #if DEPTH
-   glDeleteRenderbuffersEXT(1, &DepthRB);
+   glDeleteRenderbuffers_func(1, &DepthRB);
 #endif
 #if STENCIL
-   glDeleteRenderbuffersEXT(1, &StencilRB);
+   glDeleteRenderbuffers_func(1, &StencilRB);
 #endif
-   glDeleteFramebuffersEXT(1, &MyFB);
+   glDeleteFramebuffers_func(1, &MyFB);
 
    glDeleteTextures(1, &TexObj);
 
@@ -318,14 +318,14 @@ AttachDepthAndStencilBuffers(GLuint fbo,
 
    *depthRbOut = *stencilRbOut = 0;
 
-   glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo);
+   glBindFramebuffer_func(GL_FRAMEBUFFER_EXT, fbo);
 
    if (tryDepthStencil) {
       GLuint rb;
 
-      glGenRenderbuffersEXT(1, &rb);
-      glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, rb);
-      glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT,
+      glGenRenderbuffers_func(1, &rb);
+      glBindRenderbuffer_func(GL_RENDERBUFFER_EXT, rb);
+      glRenderbufferStorage_func(GL_RENDERBUFFER_EXT,
                                GL_DEPTH24_STENCIL8_EXT,
                                width, height);
       if (glGetError())
@@ -333,7 +333,7 @@ AttachDepthAndStencilBuffers(GLuint fbo,
 
       if (bindDepthStencil) {
          /* attach to both depth and stencil at once */
-         glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT,
+         glFramebufferRenderbuffer_func(GL_FRAMEBUFFER_EXT,
                                       GL_DEPTH_STENCIL_ATTACHMENT,
                                       GL_RENDERBUFFER_EXT, rb);
          if (glGetError())
@@ -341,21 +341,21 @@ AttachDepthAndStencilBuffers(GLuint fbo,
       }
       else {
          /* attach to depth attachment point */
-         glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT,
+         glFramebufferRenderbuffer_func(GL_FRAMEBUFFER_EXT,
                                       GL_DEPTH_ATTACHMENT_EXT,
                                       GL_RENDERBUFFER_EXT, rb);
          if (glGetError())
             return GL_FALSE;
 
          /* and attach to stencil attachment point */
-         glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT,
+         glFramebufferRenderbuffer_func(GL_FRAMEBUFFER_EXT,
                                       GL_STENCIL_ATTACHMENT_EXT,
                                       GL_RENDERBUFFER_EXT, rb);
          if (glGetError())
             return GL_FALSE;
       }
 
-      status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
+      status = glCheckFramebufferStatus_func(GL_FRAMEBUFFER_EXT);
       if (status != GL_FRAMEBUFFER_COMPLETE_EXT)
          return GL_FALSE;
 
@@ -367,22 +367,22 @@ AttachDepthAndStencilBuffers(GLuint fbo,
    {
       GLuint rb;
 
-      glGenRenderbuffersEXT(1, &rb);
-      glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, rb);
-      glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT,
+      glGenRenderbuffers_func(1, &rb);
+      glBindRenderbuffer_func(GL_RENDERBUFFER_EXT, rb);
+      glRenderbufferStorage_func(GL_RENDERBUFFER_EXT,
                                GL_DEPTH_COMPONENT,
                                width, height);
       if (glGetError())
          return GL_FALSE;
 
       /* attach to depth attachment point */
-      glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT,
+      glFramebufferRenderbuffer_func(GL_FRAMEBUFFER_EXT,
                                    GL_DEPTH_ATTACHMENT_EXT,
                                    GL_RENDERBUFFER_EXT, rb);
       if (glGetError())
          return GL_FALSE;
 
-      status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
+      status = glCheckFramebufferStatus_func(GL_FRAMEBUFFER_EXT);
       if (status != GL_FRAMEBUFFER_COMPLETE_EXT)
          return GL_FALSE;
 
@@ -393,26 +393,26 @@ AttachDepthAndStencilBuffers(GLuint fbo,
    {
       GLuint rb;
 
-      glGenRenderbuffersEXT(1, &rb);
-      glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, rb);
-      glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT,
+      glGenRenderbuffers_func(1, &rb);
+      glBindRenderbuffer_func(GL_RENDERBUFFER_EXT, rb);
+      glRenderbufferStorage_func(GL_RENDERBUFFER_EXT,
                                GL_STENCIL_INDEX,
                                width, height);
       if (glGetError())
          return GL_FALSE;
 
       /* attach to depth attachment point */
-      glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT,
+      glFramebufferRenderbuffer_func(GL_FRAMEBUFFER_EXT,
                                    GL_STENCIL_ATTACHMENT_EXT,
                                    GL_RENDERBUFFER_EXT, rb);
       if (glGetError())
          return GL_FALSE;
 
-      status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
+      status = glCheckFramebufferStatus_func(GL_FRAMEBUFFER_EXT);
       if (status != GL_FRAMEBUFFER_COMPLETE_EXT) {
-         glDeleteRenderbuffersEXT(1, depthRbOut);
+         glDeleteRenderbuffers_func(1, depthRbOut);
          *depthRbOut = 0;
-         glDeleteRenderbuffersEXT(1, &rb);
+         glDeleteRenderbuffers_func(1, &rb);
          return GL_FALSE;
       }
 
@@ -463,6 +463,37 @@ ParseArgs(int argc, char *argv[])
 }
 
 
+static void
+SetupFunctionPointers(void)
+{
+   GetExtensionFuncs();
+
+   if (Use_ARB_fbo) {
+      /* no-op: use the ARB functions as-is */
+   }
+   else {
+      /* set the ARB-flavor function pointers to point to the EXT functions */
+      glIsRenderbuffer_func = glIsRenderbufferEXT_func;
+      glBindRenderbuffer_func = glBindRenderbufferEXT_func;
+      glDeleteRenderbuffers_func = glDeleteRenderbuffersEXT_func;
+      glGenRenderbuffers_func = glGenRenderbuffersEXT_func;
+      glRenderbufferStorage_func = glRenderbufferStorageEXT_func;
+      glGetRenderbufferParameteriv_func = glGetRenderbufferParameterivEXT_func;
+      glIsFramebuffer_func = glIsFramebufferEXT_func;
+      glBindFramebuffer_func = glBindFramebufferEXT_func;
+      glDeleteFramebuffers_func = glDeleteFramebuffersEXT_func;
+      glGenFramebuffers_func = glGenFramebuffersEXT_func;
+      glCheckFramebufferStatus_func = glCheckFramebufferStatusEXT_func;
+      glFramebufferTexture1D_func = glFramebufferTexture1DEXT_func;
+      glFramebufferTexture2D_func = glFramebufferTexture2DEXT_func;
+      glFramebufferTexture3D_func = glFramebufferTexture3DEXT_func;
+      glFramebufferRenderbuffer_func = glFramebufferRenderbufferEXT_func;
+      glGetFramebufferAttachmentParameteriv_func = glGetFramebufferAttachmentParameterivEXT_func;
+      glGenerateMipmap_func = glGenerateMipmapEXT_func;
+   }
+}
+
+
 /*
  * Make FBO to render into given texture.
  */
@@ -472,10 +503,10 @@ MakeFBO_RenderTexture(GLuint TexObj)
    GLuint fb;
    GLint sizeFudge = 0;
 
-   glGenFramebuffersEXT(1, &fb);
-   glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fb);
+   glGenFramebuffers_func(1, &fb);
+   glBindFramebuffer_func(GL_FRAMEBUFFER_EXT, fb);
    /* Render color to texture */
-   glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT,
+   glFramebufferTexture2D_func(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT,
                              TexTarget, TexObj, TextureLevel);
 
    if (Use_ARB_fbo) {
@@ -512,26 +543,26 @@ MakeFBO_RenderTexture(GLuint TexObj)
    {
       GLint bits, w, h;
 
-      glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, DepthRB);
-      glGetRenderbufferParameterivEXT(GL_RENDERBUFFER_EXT,
+      glBindRenderbuffer_func(GL_RENDERBUFFER_EXT, DepthRB);
+      glGetRenderbufferParameteriv_func(GL_RENDERBUFFER_EXT,
                                       GL_RENDERBUFFER_WIDTH_EXT, &w);
-      glGetRenderbufferParameterivEXT(GL_RENDERBUFFER_EXT,
+      glGetRenderbufferParameteriv_func(GL_RENDERBUFFER_EXT,
                                       GL_RENDERBUFFER_HEIGHT_EXT, &h);
       printf("Color/Texture size: %d x %d\n", TexWidth, TexHeight);
       printf("Depth buffer size: %d x %d\n", w, h);
 
-      glGetRenderbufferParameterivEXT(GL_RENDERBUFFER_EXT,
+      glGetRenderbufferParameteriv_func(GL_RENDERBUFFER_EXT,
                                       GL_RENDERBUFFER_DEPTH_SIZE_EXT, &bits);
       printf("Depth renderbuffer size = %d bits\n", bits);
 
-      glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, StencilRB);
-      glGetRenderbufferParameterivEXT(GL_RENDERBUFFER_EXT,
+      glBindRenderbuffer_func(GL_RENDERBUFFER_EXT, StencilRB);
+      glGetRenderbufferParameteriv_func(GL_RENDERBUFFER_EXT,
                                       GL_RENDERBUFFER_STENCIL_SIZE_EXT, &bits);
       printf("Stencil renderbuffer size = %d bits\n", bits);
    }
 
    /* bind the regular framebuffer */
-   glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
+   glBindFramebuffer_func(GL_FRAMEBUFFER_EXT, 0);
 
    return fb;
 }
@@ -547,6 +578,8 @@ Init(void)
 
    printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
 
+   SetupFunctionPointers();
+
    /* lighting */
    {
       static const GLfloat mat[4] = { 1.0, 0.5, 0.5, 1.0 };
@@ -605,7 +638,6 @@ main(int argc, char *argv[])
    glutInitWindowSize(Width, Height);
    glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE);
    Win = glutCreateWindow(argv[0]);
-   glewInit();
    glutReshapeFunc(Reshape);
    glutKeyboardFunc(Key);
    glutDisplayFunc(Display);