alpha.c File Reference

#include "alpha.h"
#include "context.h"
#include "types.h"
#include "dlist.h"
#include "macros.h"

Include dependency graph for alpha.c:

Go to the source code of this file.

Functions
void	gl_AlphaFunc (GLcontext *ctx, GLenum func, GLclampf ref)
GLint	gl_alpha_test (GLcontext *ctx, GLuint n, const GLubyte alpha[], GLubyte mask[])

Function Documentation

gl_alpha_test()

GLint gl_alpha_test	(	GLcontext *	ctx,
		GLuint	n,
		const GLubyte	alpha[],
		GLubyte	mask[]
	)

Definition at line 92 of file alpha.c.

{
   GLuint i;
   GLubyte ref = ctx->Color.AlphaRefUbyte;
 
   /* switch cases ordered from most frequent to less frequent */
   switch (ctx->Color.AlphaFunc) {
      case GL_LESS:
         for (i=0;i<n;i++) {
        mask[i] &= (alpha[i] < ref);
     }
     return 1;
      case GL_LEQUAL:
         for (i=0;i<n;i++) {
        mask[i] &= (alpha[i] <= ref);
     }
     return 1;
      case GL_GEQUAL:
         for (i=0;i<n;i++) {
        mask[i] &= (alpha[i] >= ref);
     }
     return 1;
      case GL_GREATER:
         for (i=0;i<n;i++) {
        mask[i] &= (alpha[i] > ref);
     }
     return 1;
      case GL_NOTEQUAL:
         for (i=0;i<n;i++) {
        mask[i] &= (alpha[i] != ref);
     }
     return 1;
      case GL_EQUAL:
         for (i=0;i<n;i++) {
        mask[i] &= (alpha[i] == ref);
     }
     return 1;
      case GL_ALWAYS:
     /* do nothing */
     return 1;
      case GL_NEVER:
         /* caller should check for zero! */
     return 0;
      default:
     gl_problem( ctx, "Invalid alpha test in gl_alpha_test" );
         return 0;
   }
   /* Never get here */
   return 1;
}

Referenced by gl_flush_pb(), gl_write_color_span(), gl_write_monocolor_span(), and gl_write_texture_span().

gl_AlphaFunc()

void gl_AlphaFunc	(	GLcontext *	ctx,
		GLenum	func,
		GLclampf	ref
	)

Definition at line 56 of file alpha.c.

{
   if (INSIDE_BEGIN_END(ctx)) {
      gl_error( ctx, GL_INVALID_OPERATION, "glAlphaFunc" );
      return;
   }
   switch (func) {
      case GL_NEVER:
      case GL_LESS:
      case GL_EQUAL:
      case GL_LEQUAL:
      case GL_GREATER:
      case GL_NOTEQUAL:
      case GL_GEQUAL:
      case GL_ALWAYS:
         ctx->Color.AlphaFunc = func;
         ctx->Color.AlphaRef = CLAMP( ref, 0.0F, 1.0F );
         ctx->Color.AlphaRefUbyte = (GLubyte) (ctx->Color.AlphaRef
                                              * ctx->Visual->AlphaScale);
         break;
      default:
         gl_error( ctx, GL_INVALID_ENUM, "glAlphaFunc(func)" );
         break;
   }
}

Referenced by execute_list(), and init_exec_pointers().