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/*

 * Mesa 3-D graphics library

 * Version:  6.5.2

 *

 * Copyright (C) 1999-2006  Brian Paul   All Rights Reserved.

 *

 * Permission is hereby granted, free of charge, to any person obtaining a

 * copy of this software and associated documentation files (the "Software"),

 * to deal in the Software without restriction, including without limitation

 * the rights to use, copy, modify, merge, publish, distribute, sublicense,

 * and/or sell copies of the Software, and to permit persons to whom the

 * Software is furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included

 * in all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS

 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL

 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN

 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN

 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

 */

#include "main/glheader.h"

#include "main/context.h"

#include "main/macros.h"

#include "main/imports.h"

#include "s_accum.h"

#include "s_context.h"

#include "s_masking.h"

#include "s_span.h"

/* XXX this would have to change for accum buffers with more or less

 * than 16 bits per color channel.

 */

#define ACCUM_SCALE16 32767.0F

/*

 * Accumulation buffer notes

 *

 * Normally, accumulation buffer values are GLshorts with values in

 * [-32767, 32767] which represent floating point colors in [-1, 1],

 * as defined by the OpenGL specification.

 *

 * We optimize for the common case used for full-scene antialiasing:

 *    // start with accum buffer cleared to zero

 *    glAccum(GL_LOAD, w);   // or GL_ACCUM the first image

 *    glAccum(GL_ACCUM, w);

 *    ...

 *    glAccum(GL_ACCUM, w);

 *    glAccum(GL_RETURN, 1.0);

 * That is, we start with an empty accumulation buffer and accumulate

 * n images, each with weight w = 1/n.

 * In this scenario, we can simply store unscaled integer values in

 * the accum buffer instead of scaled integers.  We'll also keep track

 * of the w value so when we do GL_RETURN we simply divide the accumulated

 * values by n (n=1/w).

 * This lets us avoid _many_ int->float->int conversions.

 */

#if CHAN_BITS == 8

/* enable the optimization */

#define USE_OPTIMIZED_ACCUM  1

#else

#define USE_OPTIMIZED_ACCUM  0

#endif

/**

 * This is called when we fall out of optimized/unscaled accum buffer mode.

 * That is, we convert each unscaled accum buffer value into a scaled value

 * representing the range[-1, 1].

 */

static void

rescale_accum( struct gl_context *ctx )

{

   SWcontext *swrast = SWRAST_CONTEXT(ctx);

   struct gl_renderbuffer *rb

      = ctx->DrawBuffer->Attachment[BUFFER_ACCUM].Renderbuffer;

   const GLfloat s = swrast->_IntegerAccumScaler * (32767.0F / CHAN_MAXF);

   assert(rb);

   assert(rb->_BaseFormat == GL_RGBA);

   /* add other types in future? */

   assert(rb->DataType == GL_SHORT || rb->DataType == GL_UNSIGNED_SHORT);

   assert(swrast->_IntegerAccumMode);

   if (rb->GetPointer(ctx, rb, 0, 0)) {

      /* directly-addressable memory */

      GLuint y;

      for (y = 0; y < rb->Height; y++) {

         GLuint i;

         GLshort *acc = (GLshort *) rb->GetPointer(ctx, rb, 0, y);

         for (i = 0; i < 4 * rb->Width; i++) {

            acc[i] = (GLshort) (acc[i] * s);

         }

      }

   }

   else {

      /* use get/put row funcs */

      GLuint y;

      for (y = 0; y < rb->Height; y++) {

         GLshort accRow[MAX_WIDTH * 4];

         GLuint i;

         rb->GetRow(ctx, rb, rb->Width, 0, y, accRow);

         for (i = 0; i < 4 * rb->Width; i++) {

            accRow[i] = (GLshort) (accRow[i] * s);

         }

         rb->PutRow(ctx, rb, rb->Width, 0, y, accRow, NULL);

      }

   }

   swrast->_IntegerAccumMode = GL_FALSE;

}

/**

 * Clear the accumulation Buffer.

 */

void

_swrast_clear_accum_buffer( struct gl_context *ctx, struct gl_renderbuffer *rb )

{

   SWcontext *swrast = SWRAST_CONTEXT(ctx);

   GLuint x, y, width, height;

   /* No accumulation buffer! Not an error. */

   if (!rb || !rb->Data)

      return;

   assert(rb->_BaseFormat == GL_RGBA);

   /* add other types in future? */

   assert(rb->DataType == GL_SHORT || rb->DataType == GL_UNSIGNED_SHORT);

   /* bounds, with scissor */

   x = ctx->DrawBuffer->_Xmin;

   y = ctx->DrawBuffer->_Ymin;

   width = ctx->DrawBuffer->_Xmax - ctx->DrawBuffer->_Xmin;

   height = ctx->DrawBuffer->_Ymax - ctx->DrawBuffer->_Ymin;

   if (rb->DataType == GL_SHORT || rb->DataType == GL_UNSIGNED_SHORT) {

      const GLfloat accScale = 32767.0;

      GLshort clearVal[4];

      GLuint i;

      clearVal[0] = (GLshort) (ctx->Accum.ClearColor[0] * accScale);

      clearVal[1] = (GLshort) (ctx->Accum.ClearColor[1] * accScale);

      clearVal[2] = (GLshort) (ctx->Accum.ClearColor[2] * accScale);

      clearVal[3] = (GLshort) (ctx->Accum.ClearColor[3] * accScale);

      for (i = 0; i < height; i++) {

         rb->PutMonoRow(ctx, rb, width, x, y + i, clearVal, NULL);

      }

   }

   else {

      /* someday support other sizes */

   }

   /* update optimized accum state vars */

   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) {

#if USE_OPTIMIZED_ACCUM

      swrast->_IntegerAccumMode = GL_TRUE;

#else

      swrast->_IntegerAccumMode = GL_FALSE;

#endif

      swrast->_IntegerAccumScaler = 0.0;  /* denotes empty accum buffer */

   }

   else {

      swrast->_IntegerAccumMode = GL_FALSE;

   }

}

static void

accum_add(struct gl_context *ctx, GLfloat value,

          GLint xpos, GLint ypos, GLint width, GLint height )

{

   SWcontext *swrast = SWRAST_CONTEXT(ctx);

   struct gl_renderbuffer *rb

      = ctx->DrawBuffer->Attachment[BUFFER_ACCUM].Renderbuffer;

   assert(rb);

   /* Leave optimized accum buffer mode */

   if (swrast->_IntegerAccumMode)

      rescale_accum(ctx);

   if (rb->DataType == GL_SHORT || rb->DataType == GL_UNSIGNED_SHORT) {

      const GLshort incr = (GLshort) (value * ACCUM_SCALE16);

      if (rb->GetPointer(ctx, rb, 0, 0)) {

         GLint i, j;

         for (i = 0; i < height; i++) {

            GLshort *acc = (GLshort *) rb->GetPointer(ctx, rb, xpos, ypos + i);

            for (j = 0; j < 4 * width; j++) {

               acc[j] += incr;

            }

         }

      }

      else {

         GLint i, j;

         for (i = 0; i < height; i++) {

            GLshort accRow[4 * MAX_WIDTH];

            rb->GetRow(ctx, rb, width, xpos, ypos + i, accRow);

            for (j = 0; j < 4 * width; j++) {

               accRow[j] += incr;

            }

            rb->PutRow(ctx, rb, width, xpos, ypos + i, accRow, NULL);

         }

      }

   }

   else {

      /* other types someday */

   }

}

static void

accum_mult(struct gl_context *ctx, GLfloat mult,

           GLint xpos, GLint ypos, GLint width, GLint height )

{

   SWcontext *swrast = SWRAST_CONTEXT(ctx);

   struct gl_renderbuffer *rb

      = ctx->DrawBuffer->Attachment[BUFFER_ACCUM].Renderbuffer;

   assert(rb);

   /* Leave optimized accum buffer mode */

   if (swrast->_IntegerAccumMode)

      rescale_accum(ctx);

   if (rb->DataType == GL_SHORT || rb->DataType == GL_UNSIGNED_SHORT) {

      if (rb->GetPointer(ctx, rb, 0, 0)) {

         GLint i, j;

         for (i = 0; i < height; i++) {

            GLshort *acc = (GLshort *) rb->GetPointer(ctx, rb, xpos, ypos + i);

            for (j = 0; j < 4 * width; j++) {

               acc[j] = (GLshort) (acc[j] * mult);

            }

         }

      }

      else {

         GLint i, j;

         for (i = 0; i < height; i++) {

            GLshort accRow[4 * MAX_WIDTH];

            rb->GetRow(ctx, rb, width, xpos, ypos + i, accRow);

            for (j = 0; j < 4 * width; j++) {

               accRow[j] = (GLshort) (accRow[j] * mult);

            }

            rb->PutRow(ctx, rb, width, xpos, ypos + i, accRow, NULL);

         }

      }

   }

   else {

      /* other types someday */

   }

}

static void

accum_accum(struct gl_context *ctx, GLfloat value,

            GLint xpos, GLint ypos, GLint width, GLint height )

{

   SWcontext *swrast = SWRAST_CONTEXT(ctx);

   struct gl_renderbuffer *rb

      = ctx->DrawBuffer->Attachment[BUFFER_ACCUM].Renderbuffer;

   const GLboolean directAccess = (rb->GetPointer(ctx, rb, 0, 0) != NULL);

   assert(rb);

   if (!ctx->ReadBuffer->_ColorReadBuffer) {

      /* no read buffer - OK */

      return;

   }

   /* May have to leave optimized accum buffer mode */

   if (swrast->_IntegerAccumScaler == 0.0 && value > 0.0 && value <= 1.0)

      swrast->_IntegerAccumScaler = value;

   if (swrast->_IntegerAccumMode && value != swrast->_IntegerAccumScaler)

      rescale_accum(ctx);

   if (rb->DataType == GL_SHORT || rb->DataType == GL_UNSIGNED_SHORT) {

      const GLfloat scale = value * ACCUM_SCALE16 / CHAN_MAXF;

      GLshort accumRow[4 * MAX_WIDTH];

      GLchan rgba[MAX_WIDTH][4];

      GLint i;

      for (i = 0; i < height; i++) {

         GLshort *acc;

         if (directAccess) {

            acc = (GLshort *) rb->GetPointer(ctx, rb, xpos, ypos + i);

         }

         else {

            rb->GetRow(ctx, rb, width, xpos, ypos + i, accumRow);

            acc = accumRow;

         }

         /* read colors from color buffer */

         _swrast_read_rgba_span(ctx, ctx->ReadBuffer->_ColorReadBuffer, width,

                                xpos, ypos + i, CHAN_TYPE, rgba);

         /* do accumulation */

         if (swrast->_IntegerAccumMode) {

            /* simply add integer color values into accum buffer */

            GLint j;

            for (j = 0; j < width; j++) {

               acc[j * 4 + 0] += rgba[j][RCOMP];

               acc[j * 4 + 1] += rgba[j][GCOMP];

               acc[j * 4 + 2] += rgba[j][BCOMP];

               acc[j * 4 + 3] += rgba[j][ACOMP];

            }

         }

         else {

            /* scaled integer (or float) accum buffer */

            GLint j;

            for (j = 0; j < width; j++) {

               acc[j * 4 + 0] += (GLshort) ((GLfloat) rgba[j][RCOMP] * scale);

               acc[j * 4 + 1] += (GLshort) ((GLfloat) rgba[j][GCOMP] * scale);

               acc[j * 4 + 2] += (GLshort) ((GLfloat) rgba[j][BCOMP] * scale);

               acc[j * 4 + 3] += (GLshort) ((GLfloat) rgba[j][ACOMP] * scale);

            }

         }

         if (!directAccess) {

            rb->PutRow(ctx, rb, width, xpos, ypos + i, accumRow, NULL);

         }

      }

   }

   else {

      /* other types someday */

   }

}

static void

accum_load(struct gl_context *ctx, GLfloat value,

           GLint xpos, GLint ypos, GLint width, GLint height )

{

   SWcontext *swrast = SWRAST_CONTEXT(ctx);

   struct gl_renderbuffer *rb

      = ctx->DrawBuffer->Attachment[BUFFER_ACCUM].Renderbuffer;

   const GLboolean directAccess = (rb->GetPointer(ctx, rb, 0, 0) != NULL);

   assert(rb);

   if (!ctx->ReadBuffer->_ColorReadBuffer) {

      /* no read buffer - OK */

      return;

   }

   /* This is a change to go into optimized accum buffer mode */

   if (value > 0.0 && value <= 1.0) {

#if USE_OPTIMIZED_ACCUM

      swrast->_IntegerAccumMode = GL_TRUE;

#else

      swrast->_IntegerAccumMode = GL_FALSE;

#endif

      swrast->_IntegerAccumScaler = value;

   }

   else {

      swrast->_IntegerAccumMode = GL_FALSE;

      swrast->_IntegerAccumScaler = 0.0;

   }

   if (rb->DataType == GL_SHORT || rb->DataType == GL_UNSIGNED_SHORT) {

      const GLfloat scale = value * ACCUM_SCALE16 / CHAN_MAXF;

      GLshort accumRow[4 * MAX_WIDTH];

      GLchan rgba[MAX_WIDTH][4];

      GLint i;

      for (i = 0; i < height; i++) {

         GLshort *acc;

         if (directAccess) {

            acc = (GLshort *) rb->GetPointer(ctx, rb, xpos, ypos + i);

         }

         else {

            rb->GetRow(ctx, rb, width, xpos, ypos + i, accumRow);

            acc = accumRow;

         }

         /* read colors from color buffer */

         _swrast_read_rgba_span(ctx, ctx->ReadBuffer->_ColorReadBuffer, width,

                                xpos, ypos + i, CHAN_TYPE, rgba);

         /* do load */

         if (swrast->_IntegerAccumMode) {

            /* just copy values in */

            GLint j;

            assert(swrast->_IntegerAccumScaler > 0.0);

            assert(swrast->_IntegerAccumScaler <= 1.0);

            for (j = 0; j < width; j++) {

               acc[j * 4 + 0] = rgba[j][RCOMP];

               acc[j * 4 + 1] = rgba[j][GCOMP];

               acc[j * 4 + 2] = rgba[j][BCOMP];

               acc[j * 4 + 3] = rgba[j][ACOMP];

            }

         }

         else {

            /* scaled integer (or float) accum buffer */

            GLint j;

            for (j = 0; j < width; j++) {

               acc[j * 4 + 0] = (GLshort) ((GLfloat) rgba[j][RCOMP] * scale);

               acc[j * 4 + 1] = (GLshort) ((GLfloat) rgba[j][GCOMP] * scale);

               acc[j * 4 + 2] = (GLshort) ((GLfloat) rgba[j][BCOMP] * scale);

               acc[j * 4 + 3] = (GLshort) ((GLfloat) rgba[j][ACOMP] * scale);

            }

         }

         if (!directAccess) {

            rb->PutRow(ctx, rb, width, xpos, ypos + i, accumRow, NULL);

         }

      }

   }

}

static void

accum_return(struct gl_context *ctx, GLfloat value,

             GLint xpos, GLint ypos, GLint width, GLint height )

{

   SWcontext *swrast = SWRAST_CONTEXT(ctx);

   struct gl_framebuffer *fb = ctx->DrawBuffer;

   struct gl_renderbuffer *accumRb = fb->Attachment[BUFFER_ACCUM].Renderbuffer;

   const GLboolean directAccess

      = (accumRb->GetPointer(ctx, accumRb, 0, 0) != NULL);

   static GLchan multTable[32768];

   static GLfloat prevMult = 0.0;

   const GLfloat mult = swrast->_IntegerAccumScaler;

   const GLint max = MIN2((GLint) (256 / mult), 32767);

   /* May have to leave optimized accum buffer mode */

   if (swrast->_IntegerAccumMode && value != 1.0)

      rescale_accum(ctx);

   if (swrast->_IntegerAccumMode && swrast->_IntegerAccumScaler > 0) {

      /* build lookup table to avoid many floating point multiplies */

      GLint j;

      assert(swrast->_IntegerAccumScaler <= 1.0);

      if (mult != prevMult) {

         for (j = 0; j < max; j++)

            multTable[j] = IROUND((GLfloat) j * mult);

         prevMult = mult;

      }

   }

   if (accumRb->DataType == GL_SHORT ||

       accumRb->DataType == GL_UNSIGNED_SHORT) {

      const GLfloat scale = value * CHAN_MAXF / ACCUM_SCALE16;

      GLuint buffer;

      GLint i;

      /* XXX maybe transpose the 'i' and 'buffer' loops??? */

      for (i = 0; i < height; i++) {

         GLshort accumRow[4 * MAX_WIDTH];

         GLshort *acc;

         SWspan span;

         /* init color span */

         INIT_SPAN(span, GL_BITMAP);

         span.end = width;

         span.arrayMask = SPAN_RGBA;

         span.x = xpos;

         span.y = ypos + i;

         if (directAccess) {

            acc = (GLshort *) accumRb->GetPointer(ctx, accumRb, xpos, ypos +i);

         }

         else {

            accumRb->GetRow(ctx, accumRb, width, xpos, ypos + i, accumRow);

            acc = accumRow;

         }

         /* get the colors to return */

         if (swrast->_IntegerAccumMode) {

            GLint j;

            for (j = 0; j < width; j++) {

               ASSERT(acc[j * 4 + 0] < max);

               ASSERT(acc[j * 4 + 1] < max);

               ASSERT(acc[j * 4 + 2] < max);

               ASSERT(acc[j * 4 + 3] < max);

               span.array->rgba[j][RCOMP] = multTable[acc[j * 4 + 0]];

               span.array->rgba[j][GCOMP] = multTable[acc[j * 4 + 1]];

               span.array->rgba[j][BCOMP] = multTable[acc[j * 4 + 2]];

               span.array->rgba[j][ACOMP] = multTable[acc[j * 4 + 3]];

            }

         }

         else {

            /* scaled integer (or float) accum buffer */

            GLint j;

            for (j = 0; j < width; j++) {

#if CHAN_BITS==32

               GLchan r = acc[j * 4 + 0] * scale;

               GLchan g = acc[j * 4 + 1] * scale;

               GLchan b = acc[j * 4 + 2] * scale;

               GLchan a = acc[j * 4 + 3] * scale;

#else

               GLint r = IROUND( (GLfloat) (acc[j * 4 + 0]) * scale );

               GLint g = IROUND( (GLfloat) (acc[j * 4 + 1]) * scale );

               GLint b = IROUND( (GLfloat) (acc[j * 4 + 2]) * scale );

               GLint a = IROUND( (GLfloat) (acc[j * 4 + 3]) * scale );

#endif

               span.array->rgba[j][RCOMP] = CLAMP( r, 0, CHAN_MAX );

               span.array->rgba[j][GCOMP] = CLAMP( g, 0, CHAN_MAX );

               span.array->rgba[j][BCOMP] = CLAMP( b, 0, CHAN_MAX );

               span.array->rgba[j][ACOMP] = CLAMP( a, 0, CHAN_MAX );

            }

         }

         /* store colors */

         for (buffer = 0; buffer < fb->_NumColorDrawBuffers; buffer++) {

            struct gl_renderbuffer *rb = fb->_ColorDrawBuffers[buffer];

            const GLboolean masking = (!ctx->Color.ColorMask[buffer][RCOMP] ||

                                       !ctx->Color.ColorMask[buffer][GCOMP] ||

                                       !ctx->Color.ColorMask[buffer][BCOMP] ||

                                       !ctx->Color.ColorMask[buffer][ACOMP]);

            if (masking) {

               _swrast_mask_rgba_span(ctx, rb, &span, buffer);

            }

            rb->PutRow(ctx, rb, width, xpos, ypos + i, span.array->rgba, NULL);

         }

      }

   }

   else {

      /* other types someday */

   }

}

/**

 * Software fallback for glAccum.

 */

void

_swrast_Accum(struct gl_context *ctx, GLenum op, GLfloat value)

{

   SWcontext *swrast = SWRAST_CONTEXT(ctx);

   GLint xpos, ypos, width, height;

   if (swrast->NewState)

      _swrast_validate_derived( ctx );

   if (!ctx->DrawBuffer->Attachment[BUFFER_ACCUM].Renderbuffer) {

      _mesa_warning(ctx, "Calling glAccum() without an accumulation buffer");

      return;

   }

   swrast_render_start(ctx);

   /* Compute region after calling swrast_render_start() so that we know the

    * drawbuffer's size/bounds are up to date.

    */

   xpos = ctx->DrawBuffer->_Xmin;

   ypos = ctx->DrawBuffer->_Ymin;

   width =  ctx->DrawBuffer->_Xmax - ctx->DrawBuffer->_Xmin;

   height = ctx->DrawBuffer->_Ymax - ctx->DrawBuffer->_Ymin;

   switch (op) {

      case GL_ADD:

         if (value != 0.0F) {

            accum_add(ctx, value, xpos, ypos, width, height);

	 }

	 break;

      case GL_MULT:

         if (value != 1.0F) {

            accum_mult(ctx, value, xpos, ypos, width, height);

	 }

	 break;

      case GL_ACCUM:

         if (value != 0.0F) {

            accum_accum(ctx, value, xpos, ypos, width, height);

         }

	 break;

      case GL_LOAD:

         accum_load(ctx, value, xpos, ypos, width, height);

	 break;

      case GL_RETURN:

         accum_return(ctx, value, xpos, ypos, width, height);

	 break;

      default:

         _mesa_problem(ctx, "invalid mode in _swrast_Accum()");

         break;

   }

   swrast_render_finish(ctx);

}