mesa: rewrite accum buffer support

Implemented in terms of renderbuffer mapping/unmapping and format
packing/unpacking functions.

The swrast and state tracker code for implementing accumulation are
unused and will be removed in the next commit.

v2: don't use memcpy() in _mesa_clear_accum_buffer()
v3: don't allocate MAX_WIDTH arrays, be more careful with mapping flags

Reviewed-by: Eric Anholt <eric@anholt.net>

1 files changed, 385 insertions, 1 deletions

diff --git a/src/mesa/main/accum.c b/src/mesa/main/accum.c
index d7ed3a8..eb06bbb 100644
--- a/src/mesa/main/accum.c
+++ b/src/mesa/main/accum.c
@@ -24,7 +24,10 @@
 
 #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 "mfeatures.h"
@@ -101,7 +104,7 @@ _mesa_Accum( GLenum op, GLfloat value )
       return;
 
    if (ctx->RenderMode == GL_RENDER) {
-      ctx->Driver.Accum(ctx, op, value);
+      _mesa_accum(ctx, op, value);
    }
 }
 
@@ -123,3 +126,384 @@ _mesa_init_accum( struct gl_context *ctx )
    /* Accumulate buffer group */
    ASSIGN_4V( ctx->Accum.ClearColor, 0.0, 0.0, 0.0, 0.0 );
 }
+
+
+
+
+/**
+ * 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_SIGNED_RGBA_16) {
+      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_SIGNED_RGBA_16) {
+      const GLshort incr = (GLshort) (value * 32767.0f);
+      GLuint 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_SIGNED_RGBA_16) {
+      const GLfloat scale = value * 32767.0f;
+      GLuint i, j;
+      GLfloat (*rgba)[4];
+
+      rgba = (GLfloat (*)[4]) 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_SIGNED_RGBA_16) {
+         const GLfloat scale = value / 32767.0f;
+         GLint i, j;
+         GLfloat (*rgba)[4], (*dest)[4];
+
+         rgba = (GLfloat (*)[4]) malloc(width * 4 * sizeof(GLfloat));
+         dest = (GLfloat (*)[4]) 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.
+ */
+void
+_mesa_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:
+      _mesa_problem(ctx, "invalid mode in _mesa_accum()");
+      break;
+   }
+}