Mesa (master): mesa/copyimage: allow width/ height to not be multiples of block

[Ilia Mirkin]

Module: Mesa
Branch: master
Commit: 912babba7bf1abd3caa49f6372d581ae1afe7e84
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=912babba7bf1abd3caa49f6372d581ae1afe7e84

Author: Ilia Mirkin <imirkin at alum.mit.edu>
Date:   Sun Nov  8 04:46:38 2015 -0500

mesa/copyimage: allow width/height to not be multiples of block

For compressed textures, the image size is not necessarily a multiple of
the block size (e.g. the last mip levels). Section 18.3.2 (Copying
Between Images) of the OpenGL 4.5 Core Profile spec says:

    An INVALID_VALUE error is generated if the dimensions of either
    subregion exceeds the boundaries of the corresponding image
    object, or if the image format is compressed and the dimensions of
    the subregion fail to meet the alignment constraints of the
    format.

and Section 8.7 (Compressed Texture Images) says:

    An INVALID_OPERATION error is generated if any of the following
    conditions occurs:

      * width is not a multiple of four, and width + xoffset is not
        equal to the value of TEXTURE_WIDTH.
      * height is not a multiple of four, and height + yoffset is not
        equal to the value of TEXTURE_HEIGHT.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92860
Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>
Acked-by: Alex Deucher <alexander.deucher at amd.com>
Reviewed-by: Jason Ekstrand <jason.ekstrand at intel.com>
Reviewed-by: Ian Romanick <ian.d.romanick at intel.com>
Cc: mesa-stable at lists.freedesktop.org

---

 src/mesa/main/copyimage.c |   37 ++++++++++++++++++++++++++++++++++---
 1 file changed, 34 insertions(+), 3 deletions(-)

diff --git a/src/mesa/main/copyimage.c b/src/mesa/main/copyimage.c
index f02e842..d571d22 100644
--- a/src/mesa/main/copyimage.c
+++ b/src/mesa/main/copyimage.c
@@ -62,6 +62,8 @@ prepare_target(struct gl_context *ctx, GLuint name, GLenum target,
                struct gl_renderbuffer **renderbuffer,
                mesa_format *format,
                GLenum *internalFormat,
+               GLuint *width,
+               GLuint *height,
                const char *dbg_prefix)
 {
    if (name == 0) {
@@ -126,6 +128,8 @@ prepare_target(struct gl_context *ctx, GLuint name, GLenum target,
       *renderbuffer = rb;
       *format = rb->Format;
       *internalFormat = rb->InternalFormat;
+      *width = rb->Width;
+      *height = rb->Height;
       *tex_image = NULL;
    } else {
       struct gl_texture_object *texObj = _mesa_lookup_texture(ctx, name);
@@ -194,6 +198,8 @@ prepare_target(struct gl_context *ctx, GLuint name, GLenum target,
       *renderbuffer = NULL;
       *format = (*tex_image)->TexFormat;
       *internalFormat = (*tex_image)->InternalFormat;
+      *width = (*tex_image)->Width;
+      *height = (*tex_image)->Height;
    }
 
    return true;
@@ -423,6 +429,7 @@ _mesa_CopyImageSubData(GLuint srcName, GLenum srcTarget, GLint srcLevel,
    struct gl_renderbuffer *srcRenderbuffer, *dstRenderbuffer;
    mesa_format srcFormat, dstFormat;
    GLenum srcIntFormat, dstIntFormat;
+   GLuint src_w, src_h, dst_w, dst_h;
    GLuint src_bw, src_bh, dst_bw, dst_bh;
    int dstWidth, dstHeight, dstDepth;
    int i;
@@ -445,17 +452,41 @@ _mesa_CopyImageSubData(GLuint srcName, GLenum srcTarget, GLint srcLevel,
 
    if (!prepare_target(ctx, srcName, srcTarget, srcLevel, srcZ, srcDepth,
                        &srcTexImage, &srcRenderbuffer, &srcFormat,
-                       &srcIntFormat, "src"))
+                       &srcIntFormat, &src_w, &src_h, "src"))
       return;
 
    if (!prepare_target(ctx, dstName, dstTarget, dstLevel, dstZ, srcDepth,
                        &dstTexImage, &dstRenderbuffer, &dstFormat,
-                       &dstIntFormat, "dst"))
+                       &dstIntFormat, &dst_w, &dst_h, "dst"))
       return;
 
    _mesa_get_format_block_size(srcFormat, &src_bw, &src_bh);
+
+   /* Section 18.3.2 (Copying Between Images) of the OpenGL 4.5 Core Profile
+    * spec says:
+    *
+    *    An INVALID_VALUE error is generated if the dimensions of either
+    *    subregion exceeds the boundaries of the corresponding image object,
+    *    or if the image format is compressed and the dimensions of the
+    *    subregion fail to meet the alignment constraints of the format.
+    *
+    * and Section 8.7 (Compressed Texture Images) says:
+    *
+    *    An INVALID_OPERATION error is generated if any of the following
+    *    conditions occurs:
+    *
+    *      * width is not a multiple of four, and width + xoffset is not
+    *        equal to the value of TEXTURE_WIDTH.
+    *      * height is not a multiple of four, and height + yoffset is not
+    *        equal to the value of TEXTURE_HEIGHT.
+    *
+    * so we take that to mean that you can copy the "last" block of a
+    * compressed texture image even if it's smaller than the minimum block
+    * dimensions.
+    */
    if ((srcX % src_bw != 0) || (srcY % src_bh != 0) ||
-       (srcWidth % src_bw != 0) || (srcHeight % src_bh != 0)) {
+       (srcWidth % src_bw != 0 && (srcX + srcWidth) != src_w) ||
+       (srcHeight % src_bh != 0 && (srcY + srcHeight) != src_h)) {
       _mesa_error(ctx, GL_INVALID_VALUE,
                   "glCopyImageSubData(unaligned src rectangle)");
       return;