/*
 * Mesa 3-D graphics library
 *
 * Copyright (C) 1999-2005  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
 * THE AUTHORS OR COPYRIGHT HOLDERS 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 "glheader.h"
#include "accum.h"
#include "condrender.h"
#include "context.h"
#include "format_unpack.h"
#include "format_pack.h"
#include "imports.h"
#include "macros.h"
#include "state.h"
#include "mtypes.h"
#include "main/dispatch.h"


void GLAPIENTRY
_mesa_ClearAccum( GLfloat red, GLfloat green, GLfloat blue, GLfloat alpha )
{
   GLfloat tmp[4];
   GET_CURRENT_CONTEXT(ctx);

   tmp[0] = CLAMP( red,   -1.0F, 1.0F );
   tmp[1] = CLAMP( green, -1.0F, 1.0F );
   tmp[2] = CLAMP( blue,  -1.0F, 1.0F );
   tmp[3] = CLAMP( alpha, -1.0F, 1.0F );

   if (TEST_EQ_4V(tmp, ctx->Accum.ClearColor))
      return;

   COPY_4FV( ctx->Accum.ClearColor, tmp );
}


/**
 * Clear the accumulation buffer by mapping the renderbuffer and
 * writing the clear color to it.  Called by the driver's implementation
 * of the glClear function.
 */
void
_mesa_clear_accum_buffer(struct gl_context *ctx)
{
   GLuint x, y, width, height;
   GLubyte *accMap;
   GLint accRowStride;
   struct gl_renderbuffer *accRb;

   if (!ctx->DrawBuffer)
      return;

   accRb = ctx->DrawBuffer->Attachment[BUFFER_ACCUM].Renderbuffer;
   if (!accRb)
      return;   /* missing accum buffer, not an error */

   /* 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;

   ctx->Driver.MapRenderbuffer(ctx, accRb, x, y, width, height,
                               GL_MAP_WRITE_BIT, &accMap, &accRowStride);

   if (!accMap) {
      _mesa_error(ctx, GL_OUT_OF_MEMORY, "glAccum");
      return;
   }

   if (accRb->Format == MESA_FORMAT_RGBA_SNORM16) {
      const GLshort clearR = FLOAT_TO_SHORT(ctx->Accum.ClearColor[0]);
      const GLshort clearG = FLOAT_TO_SHORT(ctx->Accum.ClearColor[1]);
      const GLshort clearB = FLOAT_TO_SHORT(ctx->Accum.ClearColor[2]);
      const GLshort clearA = FLOAT_TO_SHORT(ctx->Accum.ClearColor[3]);
      GLuint i, j;

      for (j = 0; j < height; j++) {
         GLshort *row = (GLshort *) accMap;
         
         for (i = 0; i < width; i++) {
            row[i * 4 + 0] = clearR;
            row[i * 4 + 1] = clearG;
            row[i * 4 + 2] = clearB;
            row[i * 4 + 3] = clearA;
         }
         accMap += accRowStride;
      }
   }
   else {
      /* other types someday? */
      _mesa_warning(ctx, "unexpected accum buffer type");
   }

   ctx->Driver.UnmapRenderbuffer(ctx, accRb);
}


/**
 * if (bias)
 *    Accum += value
 * else
 *    Accum *= value
 */
static void
accum_scale_or_bias(struct gl_context *ctx, GLfloat value,
                    GLint xpos, GLint ypos, GLint width, GLint height,
                    GLboolean bias)
{
   struct gl_renderbuffer *accRb =
      ctx->DrawBuffer->Attachment[BUFFER_ACCUM].Renderbuffer;
   GLubyte *accMap;
   GLint accRowStride;

   assert(accRb);

   ctx->Driver.MapRenderbuffer(ctx, accRb, xpos, ypos, width, height,
                               GL_MAP_READ_BIT | GL_MAP_WRITE_BIT,
                               &accMap, &accRowStride);

   if (!accMap) {
      _mesa_error(ctx, GL_OUT_OF_MEMORY, "glAccum");
      return;
   }

   if (accRb->Format == MESA_FORMAT_RGBA_SNORM16) {
      const GLshort incr = (GLshort) (value * 32767.0f);
      GLint i, j;
      if (bias) {
         for (j = 0; j < height; j++) {
            GLshort *acc = (GLshort *) accMap;
            for (i = 0; i < 4 * width; i++) {
               acc[i] += incr;
            }
            accMap += accRowStride;
         }
      }
      else {
         /* scale */
         for (j = 0; j < height; j++) {
            GLshort *acc = (GLshort *) accMap;
            for (i = 0; i < 4 * width; i++) {
               acc[i] = (GLshort) (acc[i] * value);
            }
            accMap += accRowStride;
         }
      }
   }
   else {
      /* other types someday? */
   }

   ctx->Driver.UnmapRenderbuffer(ctx, accRb);
}


/**
 * if (load)
 *    Accum = ColorBuf * value
 * else
 *    Accum += ColorBuf * value
 */
static void
accum_or_load(struct gl_context *ctx, GLfloat value,
              GLint xpos, GLint ypos, GLint width, GLint height,
              GLboolean load)
{
   struct gl_renderbuffer *accRb =
      ctx->DrawBuffer->Attachment[BUFFER_ACCUM].Renderbuffer;
   struct gl_renderbuffer *colorRb = ctx->ReadBuffer->_ColorReadBuffer;
   GLubyte *accMap, *colorMap;
   GLint accRowStride, colorRowStride;
   GLbitfield mappingFlags;

   if (!colorRb) {
      /* no read buffer - OK */
      return;
   }

   assert(accRb);

   mappingFlags = GL_MAP_WRITE_BIT;
   if (!load) /* if we're accumulating */
      mappingFlags |= GL_MAP_READ_BIT;

   /* Map accum buffer */
   ctx->Driver.MapRenderbuffer(ctx, accRb, xpos, ypos, width, height,
                               mappingFlags, &accMap, &accRowStride);
   if (!accMap) {
      _mesa_error(ctx, GL_OUT_OF_MEMORY, "glAccum");
      return;
   }

   /* Map color buffer */
   ctx->Driver.MapRenderbuffer(ctx, colorRb, xpos, ypos, width, height,
                               GL_MAP_READ_BIT,
                               &colorMap, &colorRowStride);
   if (!colorMap) {
      ctx->Driver.UnmapRenderbuffer(ctx, accRb);
      _mesa_error(ctx, GL_OUT_OF_MEMORY, "glAccum");
      return;
   }

   if (accRb->Format == MESA_FORMAT_RGBA_SNORM16) {
      const GLfloat scale = value * 32767.0f;
      GLint i, j;
      GLfloat (*rgba)[4];

      rgba = malloc(width * 4 * sizeof(GLfloat));
      if (rgba) {
         for (j = 0; j < height; j++) {
            GLshort *acc = (GLshort *) accMap;

            /* read colors from source color buffer */
            _mesa_unpack_rgba_row(colorRb->Format, width, colorMap, rgba);

            if (load) {
               for (i = 0; i < width; i++) {
                  acc[i * 4 + 0] = (GLshort) (rgba[i][RCOMP] * scale);
                  acc[i * 4 + 1] = (GLshort) (rgba[i][GCOMP] * scale);
                  acc[i * 4 + 2] = (GLshort) (rgba[i][BCOMP] * scale);
                  acc[i * 4 + 3] = (GLshort) (rgba[i][ACOMP] * scale);
               }
            }
            else {
               /* accumulate */
               for (i = 0; i < width; i++) {
                  acc[i * 4 + 0] += (GLshort) (rgba[i][RCOMP] * scale);
                  acc[i * 4 + 1] += (GLshort) (rgba[i][GCOMP] * scale);
                  acc[i * 4 + 2] += (GLshort) (rgba[i][BCOMP] * scale);
                  acc[i * 4 + 3] += (GLshort) (rgba[i][ACOMP] * scale);
               }
            }

            colorMap += colorRowStride;
            accMap += accRowStride;
         }

         free(rgba);
      }
      else {
         _mesa_error(ctx, GL_OUT_OF_MEMORY, "glAccum");
      }
   }
   else {
      /* other types someday? */
   }

   ctx->Driver.UnmapRenderbuffer(ctx, accRb);
   ctx->Driver.UnmapRenderbuffer(ctx, colorRb);
}


/**
 * ColorBuffer = Accum * value
 */
static void
accum_return(struct gl_context *ctx, GLfloat value,
             GLint xpos, GLint ypos, GLint width, GLint height)
{
   struct gl_framebuffer *fb = ctx->DrawBuffer;
   struct gl_renderbuffer *accRb = fb->Attachment[BUFFER_ACCUM].Renderbuffer;
   GLubyte *accMap, *colorMap;
   GLint accRowStride, colorRowStride;
   GLuint buffer;

   /* Map accum buffer */
   ctx->Driver.MapRenderbuffer(ctx, accRb, xpos, ypos, width, height,
                               GL_MAP_READ_BIT,
                               &accMap, &accRowStride);
   if (!accMap) {
      _mesa_error(ctx, GL_OUT_OF_MEMORY, "glAccum");
      return;
   }

   /* Loop over destination buffers */
   for (buffer = 0; buffer < fb->_NumColorDrawBuffers; buffer++) {
      struct gl_renderbuffer *colorRb = 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]);
      GLbitfield mappingFlags = GL_MAP_WRITE_BIT;

      if (masking)
         mappingFlags |= GL_MAP_READ_BIT;

      /* Map color buffer */
      ctx->Driver.MapRenderbuffer(ctx, colorRb, xpos, ypos, width, height,
                                  mappingFlags, &colorMap, &colorRowStride);
      if (!colorMap) {
         _mesa_error(ctx, GL_OUT_OF_MEMORY, "glAccum");
         continue;
      }

      if (accRb->Format == MESA_FORMAT_RGBA_SNORM16) {
         const GLfloat scale = value / 32767.0f;
         GLint i, j;
         GLfloat (*rgba)[4], (*dest)[4];

         rgba = malloc(width * 4 * sizeof(GLfloat));
         dest = malloc(width * 4 * sizeof(GLfloat));

         if (rgba && dest) {
            for (j = 0; j < height; j++) {
               GLshort *acc = (GLshort *) accMap;

               for (i = 0; i < width; i++) {
                  rgba[i][0] = acc[i * 4 + 0] * scale;
                  rgba[i][1] = acc[i * 4 + 1] * scale;
                  rgba[i][2] = acc[i * 4 + 2] * scale;
                  rgba[i][3] = acc[i * 4 + 3] * scale;
               }

               if (masking) {

                  /* get existing colors from dest buffer */
                  _mesa_unpack_rgba_row(colorRb->Format, width, colorMap, dest);

                  /* use the dest colors where mask[channel] = 0 */
                  if (ctx->Color.ColorMask[buffer][RCOMP] == 0) {
                     for (i = 0; i < width; i++)
                        rgba[i][RCOMP] = dest[i][RCOMP];
                  }
                  if (ctx->Color.ColorMask[buffer][GCOMP] == 0) {
                     for (i = 0; i < width; i++)
                        rgba[i][GCOMP] = dest[i][GCOMP];
                  }
                  if (ctx->Color.ColorMask[buffer][BCOMP] == 0) {
                     for (i = 0; i < width; i++)
                        rgba[i][BCOMP] = dest[i][BCOMP];
                  }
                  if (ctx->Color.ColorMask[buffer][ACOMP] == 0) {
                     for (i = 0; i < width; i++)
                        rgba[i][ACOMP] = dest[i][ACOMP];
                  }
               }

               _mesa_pack_float_rgba_row(colorRb->Format, width,
                                         (const GLfloat (*)[4]) rgba, colorMap);

               accMap += accRowStride;
               colorMap += colorRowStride;
            }
         }
         else {
            _mesa_error(ctx, GL_OUT_OF_MEMORY, "glAccum");
         }
         free(rgba);
         free(dest);
      }
      else {
         /* other types someday? */
      }

      ctx->Driver.UnmapRenderbuffer(ctx, colorRb);
   }

   ctx->Driver.UnmapRenderbuffer(ctx, accRb);
}



/**
 * Software fallback for glAccum.  A hardware driver that supports
 * signed 16-bit color channels could implement hardware accumulation
 * operations, but no driver does so at this time.
 */
static void
accum(struct gl_context *ctx, GLenum op, GLfloat value)
{
   GLint xpos, ypos, width, height;

   if (!ctx->DrawBuffer->Attachment[BUFFER_ACCUM].Renderbuffer) {
      _mesa_warning(ctx, "Calling glAccum() without an accumulation buffer");
      return;
   }

   if (!_mesa_check_conditional_render(ctx))
      return;

   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_scale_or_bias(ctx, value, xpos, ypos, width, height, GL_TRUE);
      }
      break;
   case GL_MULT:
      if (value != 1.0F) {
         accum_scale_or_bias(ctx, value, xpos, ypos, width, height, GL_FALSE);
      }
      break;
   case GL_ACCUM:
      if (value != 0.0F) {
         accum_or_load(ctx, value, xpos, ypos, width, height, GL_FALSE);
      }
      break;
   case GL_LOAD:
      accum_or_load(ctx, value, xpos, ypos, width, height, GL_TRUE);
      break;
   case GL_RETURN:
      accum_return(ctx, value, xpos, ypos, width, height);
      break;
   default:
      unreachable("invalid mode in _mesa_Accum()");
      break;
   }
}


void 
_mesa_init_accum( struct gl_context *ctx )
{
   /* Accumulate buffer group */
   ASSIGN_4V( ctx->Accum.ClearColor, 0.0, 0.0, 0.0, 0.0 );
}


void GLAPIENTRY
_mesa_Accum( GLenum op, GLfloat value )
{
   GET_CURRENT_CONTEXT(ctx);
   FLUSH_VERTICES(ctx, 0);

   switch (op) {
   case GL_ADD:
   case GL_MULT:
   case GL_ACCUM:
   case GL_LOAD:
   case GL_RETURN:
      /* OK */
      break;
   default:
      _mesa_error(ctx, GL_INVALID_ENUM, "glAccum(op)");
      return;
   }

   if (ctx->DrawBuffer->Visual.haveAccumBuffer == 0) {
      _mesa_error(ctx, GL_INVALID_OPERATION, "glAccum(no accum buffer)");
      return;
   }

   if (ctx->DrawBuffer != ctx->ReadBuffer) {
      /* See GLX_SGI_make_current_read or WGL_ARB_make_current_read,
       * or GL_EXT_framebuffer_blit.
       */
      _mesa_error(ctx, GL_INVALID_OPERATION,
                  "glAccum(different read/draw buffers)");
      return;
   }

   if (ctx->NewState)
      _mesa_update_state(ctx);

   if (ctx->DrawBuffer->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
      _mesa_error(ctx, GL_INVALID_FRAMEBUFFER_OPERATION_EXT,
                  "glAccum(incomplete framebuffer)");
      return;
   }

   if (ctx->RasterDiscard)
      return;

   if (ctx->RenderMode == GL_RENDER) {
      accum(ctx, op, value);
   }
}