accum.h File Reference

#include "types.h"

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Functions
void	gl_alloc_accum_buffer (GLcontext *ctx)
void	gl_Accum (GLcontext *ctx, GLenum op, GLfloat value)
void	gl_ClearAccum (GLcontext *ctx, GLfloat red, GLfloat green, GLfloat blue, GLfloat alpha)
void	gl_clear_accum_buffer (GLcontext *ctx)

Function Documentation

gl_Accum()

void gl_Accum	(	GLcontext *	ctx,
		GLenum	op,
		GLfloat	value
	)

Definition at line 95 of file accum.c.

{
   GLuint xpos, ypos, width, height;
   GLfloat acc_scale;
 
   if (INSIDE_BEGIN_END(ctx)) {
      gl_error( ctx, GL_INVALID_OPERATION, "glAccum" );
      return;
   }
 
   if (ctx->Visual->AccumBits==0 || !ctx->Buffer->Accum) {
      /* No accumulation buffer! */
      gl_warning(ctx, "Calling glAccum() without an accumulation buffer");
      return;
   }
 
   if (sizeof(GLaccum)==1) {
      acc_scale = 127.0;
   }
   else if (sizeof(GLaccum)==2) {
      acc_scale = 32767.0;
   }
   else {
      /* sizeof(GLaccum) > 2 (Cray) */
      acc_scale = (float) SHRT_MAX;
   }
 
   /* Determine region to operate upon. */
   if (ctx->Scissor.Enabled) {
      xpos = ctx->Scissor.X;
      ypos = ctx->Scissor.Y;
      width = ctx->Scissor.Width;
      height = ctx->Scissor.Height;
   }
   else {
      /* whole window */
      xpos = 0;
      ypos = 0;
      width = ctx->Buffer->Width;
      height = ctx->Buffer->Height;
   }
 
   switch (op) {
      case GL_ADD:
         {
        GLaccum ival, *acc;
        GLuint i, j;
 
        ival = (GLaccum) (value * acc_scale);
        for (j=0;j<height;j++) {
           acc = ctx->Buffer->Accum
                     + (ypos * ctx->Buffer->Width + xpos) * 4;
           for (i=0;i<width;i++) {
          *acc += ival;   acc++;   /* red */
          *acc += ival;   acc++;   /* green */
          *acc += ival;   acc++;   /* blue */
          *acc += ival;   acc++;   /* alpha */
           }
           ypos++;
        }
     }
     break;
      case GL_MULT:
     {
        GLaccum *acc;
        GLuint i, j;
 
        for (j=0;j<height;j++) {
           acc = ctx->Buffer->Accum
                     + (ypos * ctx->Buffer->Width + xpos) * 4;
           for (i=0;i<width;i++) {
          *acc = (GLaccum) ( (GLfloat) *acc * value );    acc++; /*r*/
          *acc = (GLaccum) ( (GLfloat) *acc * value );    acc++; /*g*/
          *acc = (GLaccum) ( (GLfloat) *acc * value );    acc++; /*g*/
          *acc = (GLaccum) ( (GLfloat) *acc * value );    acc++; /*a*/
           }
           ypos++;
        }
     }
     break;
      case GL_ACCUM:
     {
        GLaccum *acc;
        GLubyte red[MAX_WIDTH], green[MAX_WIDTH];
        GLubyte blue[MAX_WIDTH], alpha[MAX_WIDTH];
        GLfloat rscale, gscale, bscale, ascale;
        GLuint i, j;
 
        (void) (*ctx->Driver.SetBuffer)( ctx, ctx->Pixel.ReadBuffer );
 
        /* Accumulate */
        rscale = value * acc_scale * ctx->Visual->InvRedScale;
        gscale = value * acc_scale * ctx->Visual->InvGreenScale;
        bscale = value * acc_scale * ctx->Visual->InvBlueScale;
        ascale = value * acc_scale * ctx->Visual->InvAlphaScale;
        for (j=0;j<height;j++) {
           (*ctx->Driver.ReadColorSpan)( ctx, width, xpos, ypos,
                                             red, green, blue, alpha);
           acc = ctx->Buffer->Accum
                     + (ypos * ctx->Buffer->Width + xpos) * 4;
           for (i=0;i<width;i++) {
          *acc += (GLaccum) ( (GLfloat) red[i]   * rscale );  acc++;
          *acc += (GLaccum) ( (GLfloat) green[i] * gscale );  acc++;
          *acc += (GLaccum) ( (GLfloat) blue[i]  * bscale );  acc++;
          *acc += (GLaccum) ( (GLfloat) alpha[i] * ascale );  acc++;
           }
           ypos++;
        }
 
        (void) (*ctx->Driver.SetBuffer)( ctx, ctx->Color.DrawBuffer );
     }
     break;
      case GL_LOAD:
     {
        GLaccum *acc;
        GLubyte red[MAX_WIDTH], green[MAX_WIDTH];
        GLubyte blue[MAX_WIDTH], alpha[MAX_WIDTH];
        GLfloat rscale, gscale, bscale, ascale;
        GLuint i, j;
 
        (void) (*ctx->Driver.SetBuffer)( ctx, ctx->Pixel.ReadBuffer );
 
        /* Load accumulation buffer */
        rscale = value * acc_scale * ctx->Visual->InvRedScale;
        gscale = value * acc_scale * ctx->Visual->InvGreenScale;
        bscale = value * acc_scale * ctx->Visual->InvBlueScale;
        ascale = value * acc_scale * ctx->Visual->InvAlphaScale;
        for (j=0;j<height;j++) {
           (*ctx->Driver.ReadColorSpan)( ctx, width, xpos, ypos,
                                             red, green, blue, alpha);
           acc = ctx->Buffer->Accum
                     + (ypos * ctx->Buffer->Width + xpos) * 4;
           for (i=0;i<width;i++) {
          *acc++ = (GLaccum) ( (GLfloat) red[i]   * rscale );
          *acc++ = (GLaccum) ( (GLfloat) green[i] * gscale );
          *acc++ = (GLaccum) ( (GLfloat) blue[i]  * bscale );
          *acc++ = (GLaccum) ( (GLfloat) alpha[i] * ascale );
           }
           ypos++;
        }
 
        (void) (*ctx->Driver.SetBuffer)( ctx, ctx->Color.DrawBuffer );
     }
     break;
      case GL_RETURN:
     {
        GLubyte red[MAX_WIDTH], green[MAX_WIDTH];
        GLubyte blue[MAX_WIDTH], alpha[MAX_WIDTH];
        GLaccum *acc;
        GLfloat rscale, gscale, bscale, ascale;
        GLint rmax, gmax, bmax, amax;
        GLuint i, j;
 
        rscale = value / acc_scale * ctx->Visual->RedScale;
        gscale = value / acc_scale * ctx->Visual->GreenScale;
        bscale = value / acc_scale * ctx->Visual->BlueScale;
        ascale = value / acc_scale * ctx->Visual->AlphaScale;
        rmax = (GLint) ctx->Visual->RedScale;
        gmax = (GLint) ctx->Visual->GreenScale;
        bmax = (GLint) ctx->Visual->BlueScale;
        amax = (GLint) ctx->Visual->AlphaScale;
        for (j=0;j<height;j++) {
           acc = ctx->Buffer->Accum
                     + (ypos * ctx->Buffer->Width + xpos) * 4;
           for (i=0;i<width;i++) {
          GLint r, g, b, a;
          r = (GLint) ( (GLfloat) (*acc++) * rscale + 0.5F );
          g = (GLint) ( (GLfloat) (*acc++) * gscale + 0.5F );
          b = (GLint) ( (GLfloat) (*acc++) * bscale + 0.5F );
          a = (GLint) ( (GLfloat) (*acc++) * ascale + 0.5F );
          red[i]   = CLAMP( r, 0, rmax );
          green[i] = CLAMP( g, 0, gmax );
          blue[i]  = CLAMP( b, 0, bmax );
          alpha[i] = CLAMP( a, 0, amax );
           }
           (*ctx->Driver.WriteColorSpan)( ctx, width, xpos, ypos,
                                              red, green, blue, alpha, NULL );
           ypos++;
        }
     }
     break;
      default:
         gl_error( ctx, GL_INVALID_ENUM, "glAccum" );
   }
}

Referenced by execute_list(), and init_exec_pointers().

gl_alloc_accum_buffer()

void gl_alloc_accum_buffer

(

GLcontext *

ctx

)

Definition at line 59 of file accum.c.

{
   GLint n;
 
   if (ctx->Buffer->Accum) {
      free( ctx->Buffer->Accum );
      ctx->Buffer->Accum = NULL;
   }
 
   /* allocate accumulation buffer if not already present */
   n = ctx->Buffer->Width * ctx->Buffer->Height * 4 * sizeof(GLaccum);
   ctx->Buffer->Accum = (GLaccum *) malloc( n );
   if (!ctx->Buffer->Accum) {
      /* unable to setup accumulation buffer */
      gl_error( ctx, GL_OUT_OF_MEMORY, "glAccum" );
   }
}

Referenced by gl_ResizeBuffersMESA().

gl_clear_accum_buffer()

void gl_clear_accum_buffer

(

GLcontext *

ctx

)

Definition at line 287 of file accum.c.

{
   GLuint buffersize;
   GLfloat acc_scale;
 
   if (ctx->Visual->AccumBits==0) {
      /* No accumulation buffer! */
      return;
   }
 
   if (sizeof(GLaccum)==1) {
      acc_scale = 127.0;
   }
   else if (sizeof(GLaccum)==2) {
      acc_scale = 32767.0;
   }
   else {
      /* sizeof(GLaccum) > 2 (Cray) */
      acc_scale = (float) SHRT_MAX;
   }
 
   /* number of pixels */
   buffersize = ctx->Buffer->Width * ctx->Buffer->Height;
 
   if (!ctx->Buffer->Accum) {
      /* try to alloc accumulation buffer */
      ctx->Buffer->Accum = (GLaccum *)
                       malloc( buffersize * 4 * sizeof(GLaccum) );
   }
 
   if (ctx->Buffer->Accum) {
      if (ctx->Scissor.Enabled) {
     /* Limit clear to scissor box */
     GLaccum r, g, b, a;
     GLint i, j;
         GLint width, height;
         GLaccum *row;
     r = (GLaccum) (ctx->Accum.ClearColor[0] * acc_scale);
     g = (GLaccum) (ctx->Accum.ClearColor[1] * acc_scale);
     b = (GLaccum) (ctx->Accum.ClearColor[2] * acc_scale);
     a = (GLaccum) (ctx->Accum.ClearColor[3] * acc_scale);
         /* size of region to clear */
         width = 4 * (ctx->Buffer->Xmax - ctx->Buffer->Xmin + 1);
         height = ctx->Buffer->Ymax - ctx->Buffer->Ymin + 1;
         /* ptr to first element to clear */
         row = ctx->Buffer->Accum
               + 4 * (ctx->Buffer->Ymin * ctx->Buffer->Width
                      + ctx->Buffer->Xmin);
         for (j=0;j<height;j++) {
            for (i=0;i<width;i+=4) {
               row[i+0] = r;
               row[i+1] = g;
               row[i+2] = b;
               row[i+3] = a;
        }
            row += 4 * ctx->Buffer->Width;
     }
      }
      else {
     /* clear whole buffer */
     if (ctx->Accum.ClearColor[0]==0.0 &&
         ctx->Accum.ClearColor[1]==0.0 &&
         ctx->Accum.ClearColor[2]==0.0 &&
         ctx->Accum.ClearColor[3]==0.0) {
        /* Black */
        MEMSET( ctx->Buffer->Accum, 0, buffersize * 4 * sizeof(GLaccum) );
     }
     else {
        /* Not black */
        GLaccum *acc, r, g, b, a;
        GLuint i;
 
        acc = ctx->Buffer->Accum;
        r = (GLaccum) (ctx->Accum.ClearColor[0] * acc_scale);
        g = (GLaccum) (ctx->Accum.ClearColor[1] * acc_scale);
        b = (GLaccum) (ctx->Accum.ClearColor[2] * acc_scale);
        a = (GLaccum) (ctx->Accum.ClearColor[3] * acc_scale);
        for (i=0;i<buffersize;i++) {
           *acc++ = r;
           *acc++ = g;
           *acc++ = b;
           *acc++ = a;
        }
     }
      }
   }
}

Referenced by gl_Clear().

gl_ClearAccum()

void gl_ClearAccum	(	GLcontext *	ctx,
		GLfloat	red,
		GLfloat	green,
		GLfloat	blue,
		GLfloat	alpha
	)

Definition at line 79 of file accum.c.

{
   if (INSIDE_BEGIN_END(ctx)) {
      gl_error( ctx, GL_INVALID_OPERATION, "glAccum" );
      return;
   }
   ctx->Accum.ClearColor[0] = CLAMP( red, -1.0, 1.0 );
   ctx->Accum.ClearColor[1] = CLAMP( green, -1.0, 1.0 );
   ctx->Accum.ClearColor[2] = CLAMP( blue, -1.0, 1.0 );
   ctx->Accum.ClearColor[3] = CLAMP( alpha, -1.0, 1.0 );
}

Referenced by execute_list(), and init_exec_pointers().