mesa: move swrast ReadPixels code into core Mesa

The swrast ReadPixels code has no dependencies on swrast since moving
to Map/UnmapRenderbuffer().  We'll be able to remove s_readpix.c and
remove the state tracker's glReadPixels code next.

Acked-by: Eric Anholt <[email protected]>

2 files changed, 493 insertions, 0 deletions

diff --git a/src/mesa/main/readpix.c b/src/mesa/main/readpix.c
index 84c5b22286a..855061815f7 100644
--- a/src/mesa/main/readpix.c
+++ b/src/mesa/main/readpix.c
@@ -30,13 +30,497 @@
 #include "readpix.h"
 #include "framebuffer.h"
 #include "formats.h"
+#include "format_unpack.h"
 #include "image.h"
 #include "mtypes.h"
+#include "pack.h"
 #include "pbo.h"
 #include "state.h"
 
 
 /**
+ * Tries to implement glReadPixels() of GL_DEPTH_COMPONENT using memcpy of the
+ * mapping.
+ */
+static GLboolean
+fast_read_depth_pixels( struct gl_context *ctx,
+			GLint x, GLint y,
+			GLsizei width, GLsizei height,
+			GLenum type, GLvoid *pixels,
+			const struct gl_pixelstore_attrib *packing )
+{
+   struct gl_framebuffer *fb = ctx->ReadBuffer;
+   struct gl_renderbuffer *rb = fb->Attachment[BUFFER_DEPTH].Renderbuffer;
+   GLubyte *map, *dst;
+   int stride, dstStride, j;
+
+   if (ctx->Pixel.DepthScale != 1.0 || ctx->Pixel.DepthBias != 0.0)
+      return GL_FALSE;
+
+   if (packing->SwapBytes)
+      return GL_FALSE;
+
+   if (_mesa_get_format_datatype(rb->Format) != GL_UNSIGNED_INT)
+      return GL_FALSE;
+
+   if (!((type == GL_UNSIGNED_SHORT && rb->Format == MESA_FORMAT_Z16) ||
+	 type == GL_UNSIGNED_INT))
+      return GL_FALSE;
+
+   ctx->Driver.MapRenderbuffer(ctx, rb, x, y, width, height, GL_MAP_READ_BIT,
+			       &map, &stride);
+
+   dstStride = _mesa_image_row_stride(packing, width, GL_DEPTH_COMPONENT, type);
+   dst = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
+					   GL_DEPTH_COMPONENT, type, 0, 0);
+
+   for (j = 0; j < height; j++) {
+      if (type == GL_UNSIGNED_INT) {
+	 _mesa_unpack_uint_z_row(rb->Format, width, map, (GLuint *)dst);
+      } else {
+	 ASSERT(type == GL_UNSIGNED_SHORT && rb->Format == MESA_FORMAT_Z16);
+	 memcpy(dst, map, width * 2);
+      }
+
+      map += stride;
+      dst += dstStride;
+   }
+   ctx->Driver.UnmapRenderbuffer(ctx, rb);
+
+   return GL_TRUE;
+}
+
+/**
+ * Read pixels for format=GL_DEPTH_COMPONENT.
+ */
+static void
+read_depth_pixels( struct gl_context *ctx,
+                   GLint x, GLint y,
+                   GLsizei width, GLsizei height,
+                   GLenum type, GLvoid *pixels,
+                   const struct gl_pixelstore_attrib *packing )
+{
+   struct gl_framebuffer *fb = ctx->ReadBuffer;
+   struct gl_renderbuffer *rb = fb->Attachment[BUFFER_DEPTH].Renderbuffer;
+   GLint j;
+   GLubyte *dst, *map;
+   int dstStride, stride;
+
+   if (!rb)
+      return;
+
+   /* clipping should have been done already */
+   ASSERT(x >= 0);
+   ASSERT(y >= 0);
+   ASSERT(x + width <= (GLint) rb->Width);
+   ASSERT(y + height <= (GLint) rb->Height);
+   /* width should never be > MAX_WIDTH since we did clipping earlier */
+   ASSERT(width <= MAX_WIDTH);
+
+   if (fast_read_depth_pixels(ctx, x, y, width, height, type, pixels, packing))
+      return;
+
+   dstStride = _mesa_image_row_stride(packing, width, GL_DEPTH_COMPONENT, type);
+   dst = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
+					   GL_DEPTH_COMPONENT, type, 0, 0);
+
+   ctx->Driver.MapRenderbuffer(ctx, rb, x, y, width, height, GL_MAP_READ_BIT,
+			       &map, &stride);
+
+   /* General case (slower) */
+   for (j = 0; j < height; j++, y++) {
+      GLfloat depthValues[MAX_WIDTH];
+      _mesa_unpack_float_z_row(rb->Format, width, map, depthValues);
+      _mesa_pack_depth_span(ctx, width, dst, type, depthValues, packing);
+
+      dst += dstStride;
+      map += stride;
+   }
+
+   ctx->Driver.UnmapRenderbuffer(ctx, rb);
+}
+
+
+/**
+ * Read pixels for format=GL_STENCIL_INDEX.
+ */
+static void
+read_stencil_pixels( struct gl_context *ctx,
+                     GLint x, GLint y,
+                     GLsizei width, GLsizei height,
+                     GLenum type, GLvoid *pixels,
+                     const struct gl_pixelstore_attrib *packing )
+{
+   struct gl_framebuffer *fb = ctx->ReadBuffer;
+   struct gl_renderbuffer *rb = fb->Attachment[BUFFER_STENCIL].Renderbuffer;
+   GLint j;
+   GLubyte *map;
+   GLint stride;
+
+   if (!rb)
+      return;
+
+   /* width should never be > MAX_WIDTH since we did clipping earlier */
+   ASSERT(width <= MAX_WIDTH);
+
+   ctx->Driver.MapRenderbuffer(ctx, rb, x, y, width, height, GL_MAP_READ_BIT,
+			       &map, &stride);
+
+   /* process image row by row */
+   for (j = 0; j < height; j++) {
+      GLvoid *dest;
+      GLubyte stencil[MAX_WIDTH];
+
+      _mesa_unpack_ubyte_stencil_row(rb->Format, width, map, stencil);
+      dest = _mesa_image_address2d(packing, pixels, width, height,
+                                   GL_STENCIL_INDEX, type, j, 0);
+
+      _mesa_pack_stencil_span(ctx, width, type, dest, stencil, packing);
+
+      map += stride;
+   }
+
+   ctx->Driver.UnmapRenderbuffer(ctx, rb);
+}
+
+static GLboolean
+fast_read_rgba_pixels_memcpy( struct gl_context *ctx,
+			      GLint x, GLint y,
+			      GLsizei width, GLsizei height,
+			      GLenum format, GLenum type,
+			      GLvoid *pixels,
+			      const struct gl_pixelstore_attrib *packing,
+			      GLbitfield transferOps )
+{
+   struct gl_renderbuffer *rb = ctx->ReadBuffer->_ColorReadBuffer;
+   GLubyte *dst, *map;
+   int dstStride, stride, j, texelBytes;
+
+   if (!_mesa_format_matches_format_and_type(rb->Format, format, type))
+      return GL_FALSE;
+
+   /* check for things we can't handle here */
+   if (packing->SwapBytes ||
+       packing->LsbFirst) {
+      return GL_FALSE;
+   }
+
+   dstStride = _mesa_image_row_stride(packing, width, format, type);
+   dst = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
+					   format, type, 0, 0);
+
+   ctx->Driver.MapRenderbuffer(ctx, rb, x, y, width, height, GL_MAP_READ_BIT,
+			       &map, &stride);
+
+   texelBytes = _mesa_get_format_bytes(rb->Format);
+   for (j = 0; j < height; j++) {
+      memcpy(dst, map, width * texelBytes);
+      dst += dstStride;
+      map += stride;
+   }
+
+   ctx->Driver.UnmapRenderbuffer(ctx, rb);
+
+   return GL_TRUE;
+}
+
+static GLboolean
+slow_read_rgba_pixels( struct gl_context *ctx,
+		       GLint x, GLint y,
+		       GLsizei width, GLsizei height,
+		       GLenum format, GLenum type,
+		       GLvoid *pixels,
+		       const struct gl_pixelstore_attrib *packing,
+		       GLbitfield transferOps )
+{
+   struct gl_renderbuffer *rb = ctx->ReadBuffer->_ColorReadBuffer;
+   const gl_format rbFormat = _mesa_get_srgb_format_linear(rb->Format);
+   union {
+      float f[MAX_WIDTH][4];
+      unsigned int i[MAX_WIDTH][4];
+   } rgba;
+   GLubyte *dst, *map;
+   int dstStride, stride, j;
+
+   dstStride = _mesa_image_row_stride(packing, width, format, type);
+   dst = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
+					   format, type, 0, 0);
+
+   ctx->Driver.MapRenderbuffer(ctx, rb, x, y, width, height, GL_MAP_READ_BIT,
+			       &map, &stride);
+
+   for (j = 0; j < height; j++) {
+      if (_mesa_is_integer_format(format)) {
+	 _mesa_unpack_int_rgba_row(rbFormat, width, map, rgba.i);
+	 _mesa_pack_rgba_span_int(ctx, width, rgba.i, format, type, dst);
+      } else {
+	 _mesa_unpack_rgba_row(rbFormat, width, map, rgba.f);
+	 _mesa_pack_rgba_span_float(ctx, width, rgba.f, format, type, dst,
+				    packing, transferOps);
+      }
+      dst += dstStride;
+      map += stride;
+   }
+
+   ctx->Driver.UnmapRenderbuffer(ctx, rb);
+
+   return GL_TRUE;
+}
+
+/*
+ * Read R, G, B, A, RGB, L, or LA pixels.
+ */
+static void
+read_rgba_pixels( struct gl_context *ctx,
+                  GLint x, GLint y,
+                  GLsizei width, GLsizei height,
+                  GLenum format, GLenum type, GLvoid *pixels,
+                  const struct gl_pixelstore_attrib *packing )
+{
+   GLbitfield transferOps = ctx->_ImageTransferState;
+   struct gl_framebuffer *fb = ctx->ReadBuffer;
+   struct gl_renderbuffer *rb = fb->_ColorReadBuffer;
+
+   if (!rb)
+      return;
+
+   if ((ctx->Color._ClampReadColor == GL_TRUE || type != GL_FLOAT) &&
+       !_mesa_is_integer_format(format)) {
+      transferOps |= IMAGE_CLAMP_BIT;
+   }
+
+   if (!transferOps) {
+      /* Try the optimized paths first. */
+      if (fast_read_rgba_pixels_memcpy(ctx, x, y, width, height,
+				       format, type, pixels, packing,
+				       transferOps)) {
+	 return;
+      }
+   }
+
+   slow_read_rgba_pixels(ctx, x, y, width, height,
+			 format, type, pixels, packing, transferOps);
+}
+
+/**
+ * For a packed depth/stencil buffer being read as depth/stencil, just memcpy the
+ * data (possibly swapping 8/24 vs 24/8 as we go).
+ */
+static GLboolean
+fast_read_depth_stencil_pixels(struct gl_context *ctx,
+			       GLint x, GLint y,
+			       GLsizei width, GLsizei height,
+			       GLubyte *dst, int dstStride)
+{
+   struct gl_framebuffer *fb = ctx->ReadBuffer;
+   struct gl_renderbuffer *rb = fb->Attachment[BUFFER_DEPTH].Renderbuffer;
+   struct gl_renderbuffer *stencilRb = fb->Attachment[BUFFER_STENCIL].Renderbuffer;
+   GLubyte *map;
+   int stride, i;
+
+   if (rb != stencilRb)
+      return GL_FALSE;
+
+   if (rb->Format != MESA_FORMAT_Z24_S8 &&
+       rb->Format != MESA_FORMAT_S8_Z24)
+      return GL_FALSE;
+
+   ctx->Driver.MapRenderbuffer(ctx, rb, x, y, width, height, GL_MAP_READ_BIT,
+			       &map, &stride);
+
+   for (i = 0; i < height; i++) {
+      _mesa_unpack_uint_24_8_depth_stencil_row(rb->Format, width,
+					       map, (GLuint *)dst);
+      map += stride;
+      dst += dstStride;
+   }
+
+   ctx->Driver.UnmapRenderbuffer(ctx, rb);
+
+   return GL_TRUE;
+}
+
+
+/**
+ * For non-float-depth and stencil buffers being read as 24/8 depth/stencil,
+ * copy the integer data directly instead of converting depth to float and
+ * re-packing.
+ */
+static GLboolean
+fast_read_depth_stencil_pixels_separate(struct gl_context *ctx,
+					GLint x, GLint y,
+					GLsizei width, GLsizei height,
+					uint32_t *dst, int dstStride)
+{
+   struct gl_framebuffer *fb = ctx->ReadBuffer;
+   struct gl_renderbuffer *depthRb = fb->Attachment[BUFFER_DEPTH].Renderbuffer;
+   struct gl_renderbuffer *stencilRb = fb->Attachment[BUFFER_STENCIL].Renderbuffer;
+   GLubyte *depthMap, *stencilMap;
+   int depthStride, stencilStride, i, j;
+
+   if (_mesa_get_format_datatype(depthRb->Format) != GL_UNSIGNED_INT)
+      return GL_FALSE;
+
+   ctx->Driver.MapRenderbuffer(ctx, depthRb, x, y, width, height,
+			       GL_MAP_READ_BIT, &depthMap, &depthStride);
+   ctx->Driver.MapRenderbuffer(ctx, stencilRb, x, y, width, height,
+			       GL_MAP_READ_BIT, &stencilMap, &stencilStride);
+
+   for (j = 0; j < height; j++) {
+      GLubyte stencilVals[MAX_WIDTH];
+
+      _mesa_unpack_uint_z_row(depthRb->Format, width, depthMap, dst);
+      _mesa_unpack_ubyte_stencil_row(stencilRb->Format, width,
+				     stencilMap, stencilVals);
+
+      for (i = 0; i < width; i++) {
+	 dst[i] = (dst[i] & 0xffffff00) | stencilVals[i];
+      }
+
+      depthMap += depthStride;
+      stencilMap += stencilStride;
+      dst += dstStride / 4;
+   }
+
+   ctx->Driver.UnmapRenderbuffer(ctx, depthRb);
+   ctx->Driver.UnmapRenderbuffer(ctx, stencilRb);
+
+   return GL_TRUE;
+}
+
+static void
+slow_read_depth_stencil_pixels_separate(struct gl_context *ctx,
+					GLint x, GLint y,
+					GLsizei width, GLsizei height,
+					GLenum type,
+					const struct gl_pixelstore_attrib *packing,
+					GLubyte *dst, int dstStride)
+{
+   struct gl_framebuffer *fb = ctx->ReadBuffer;
+   struct gl_renderbuffer *depthRb = fb->Attachment[BUFFER_DEPTH].Renderbuffer;
+   struct gl_renderbuffer *stencilRb = fb->Attachment[BUFFER_STENCIL].Renderbuffer;
+   GLubyte *depthMap, *stencilMap;
+   int depthStride, stencilStride, j;
+
+   ctx->Driver.MapRenderbuffer(ctx, depthRb, x, y, width, height,
+			       GL_MAP_READ_BIT, &depthMap, &depthStride);
+   ctx->Driver.MapRenderbuffer(ctx, stencilRb, x, y, width, height,
+			       GL_MAP_READ_BIT, &stencilMap, &stencilStride);
+
+   for (j = 0; j < height; j++) {
+      GLubyte stencilVals[MAX_WIDTH];
+      GLfloat depthVals[MAX_WIDTH];
+
+      _mesa_unpack_float_z_row(depthRb->Format, width, depthMap, depthVals);
+      _mesa_unpack_ubyte_stencil_row(stencilRb->Format, width,
+				     stencilMap, stencilVals);
+
+      _mesa_pack_depth_stencil_span(ctx, width, type, (GLuint *)dst,
+				    depthVals, stencilVals, packing);
+
+      depthMap += depthStride;
+      stencilMap += stencilStride;
+      dst += dstStride;
+   }
+
+   ctx->Driver.UnmapRenderbuffer(ctx, depthRb);
+   ctx->Driver.UnmapRenderbuffer(ctx, stencilRb);
+}
+
+
+/**
+ * Read combined depth/stencil values.
+ * We'll have already done error checking to be sure the expected
+ * depth and stencil buffers really exist.
+ */
+static void
+read_depth_stencil_pixels(struct gl_context *ctx,
+                          GLint x, GLint y,
+                          GLsizei width, GLsizei height,
+                          GLenum type, GLvoid *pixels,
+                          const struct gl_pixelstore_attrib *packing )
+{
+   const GLboolean scaleOrBias
+      = ctx->Pixel.DepthScale != 1.0 || ctx->Pixel.DepthBias != 0.0;
+   const GLboolean stencilTransfer = ctx->Pixel.IndexShift
+      || ctx->Pixel.IndexOffset || ctx->Pixel.MapStencilFlag;
+   GLubyte *dst;
+   int dstStride;
+
+   dst = (GLubyte *) _mesa_image_address2d(packing, pixels,
+					   width, height,
+					   GL_DEPTH_STENCIL_EXT,
+					   type, 0, 0);
+   dstStride = _mesa_image_row_stride(packing, width,
+				      GL_DEPTH_STENCIL_EXT, type);
+
+   /* Fast 24/8 reads. */
+   if (type == GL_UNSIGNED_INT_24_8 &&
+       !scaleOrBias && !stencilTransfer && !packing->SwapBytes) {
+      if (fast_read_depth_stencil_pixels(ctx, x, y, width, height,
+					 dst, dstStride))
+	 return;
+
+      if (fast_read_depth_stencil_pixels_separate(ctx, x, y, width, height,
+						  (uint32_t *)dst, dstStride))
+	 return;
+   }
+
+   slow_read_depth_stencil_pixels_separate(ctx, x, y, width, height,
+					   type, packing,
+					   dst, dstStride);
+}
+
+
+
+/**
+ * Software fallback routine for ctx->Driver.ReadPixels().
+ * By time we get here, all error checking will have been done.
+ */
+void
+_mesa_readpixels(struct gl_context *ctx,
+                 GLint x, GLint y, GLsizei width, GLsizei height,
+                 GLenum format, GLenum type,
+                 const struct gl_pixelstore_attrib *packing,
+                 GLvoid *pixels)
+{
+   struct gl_pixelstore_attrib clippedPacking = *packing;
+
+   if (ctx->NewState)
+      _mesa_update_state(ctx);
+
+   /* Do all needed clipping here, so that we can forget about it later */
+   if (_mesa_clip_readpixels(ctx, &x, &y, &width, &height, &clippedPacking)) {
+
+      pixels = _mesa_map_pbo_dest(ctx, &clippedPacking, pixels);
+
+      if (pixels) {
+         switch (format) {
+         case GL_STENCIL_INDEX:
+            read_stencil_pixels(ctx, x, y, width, height, type, pixels,
+                                &clippedPacking);
+            break;
+         case GL_DEPTH_COMPONENT:
+            read_depth_pixels(ctx, x, y, width, height, type, pixels,
+                              &clippedPacking);
+            break;
+         case GL_DEPTH_STENCIL_EXT:
+            read_depth_stencil_pixels(ctx, x, y, width, height, type, pixels,
+                                      &clippedPacking);
+            break;
+         default:
+            /* all other formats should be color formats */
+            read_rgba_pixels(ctx, x, y, width, height, format, type, pixels,
+                             &clippedPacking);
+         }
+
+         _mesa_unmap_pbo_dest(ctx, &clippedPacking);
+      }
+   }
+}
+
+
+/**
  * Do error checking of the format/type parameters to glReadPixels and
  * glDrawPixels.
  * \param drawing if GL_TRUE do checking for DrawPixels, else do checking
diff --git a/src/mesa/main/readpix.h b/src/mesa/main/readpix.h
index f6bb3d6e273..6caaf3adce1 100644
--- a/src/mesa/main/readpix.h
+++ b/src/mesa/main/readpix.h
@@ -30,11 +30,20 @@
 #include "glheader.h"
 
 struct gl_context;
+struct gl_pixelstore_attrib;
+
 
 extern GLboolean
 _mesa_error_check_format_type(struct gl_context *ctx, GLenum format, GLenum type,
                               GLboolean drawing);
 
+extern void
+_mesa_readpixels(struct gl_context *ctx,
+                 GLint x, GLint y, GLsizei width, GLsizei height,
+                 GLenum format, GLenum type,
+                 const struct gl_pixelstore_attrib *packing,
+                 GLvoid *pixels);
+
 extern void GLAPIENTRY
 _mesa_ReadPixels( GLint x, GLint y, GLsizei width, GLsizei height,
                   GLenum format, GLenum type, GLvoid *pixels );