On Wed, Jul 22, 2015 at 7:10 AM, Iago Toral <ito...@igalia.com> wrote: > The problem here is that the _mesa_meta_BlitFramebuffer is not setting > G/B channels to 0.0 when doing Luminance/Intensity to RGBA conversions, > so why not implement the fix in _mesa_meta_BlitFramebuffer directly? The > GL spec expects frambuffer blits to handle these conversions properly, > so it looks like a win for all uses of that function. > I couldn't find an OpenGL spec reference suggesting this conversion in case of glBlitFrameBuffer.
What I found supports the current behavior of glBlitFrameBuffer: See table 3.23 on page 220 (of pdf) of glspec30.20080811. Some relevant text from https://www.opengl.org/wiki/Image_Format: "When a GL_RED format is sampled in a shader, the resulting vec4 is (Red, 0, 0, 1). When a GL_INTENSITY format is sampled, the resulting vec4 is (I, I, I, I). The single intensity value is read into all four components. For GL_LUMINANCE, the result is (L, L, L, 1). There is also a two-channel GL_LUMINANCE_ALPHA format, which gives (L, L, L, A)." I think glBlitFrameBuffer should also follow this being a drawing operation. What do you think? > Iago > > On Fri, 2015-07-17 at 10:28 -0700, Anuj Phogat wrote: >> After recent addition of pbo testing in piglit test getteximage-luminance, >> it fails on i965. This patch makes a sub test pass. >> >> This patch adds a clear color operation to meta pbo path, which I think is >> better than falling back to software path. >> >> V2: Fix color mask for GL_LUMINANCE_ALPHA >> >> Signed-off-by: Anuj Phogat <anuj.pho...@gmail.com> >> Cc: <mesa-sta...@lists.freedesktop.org> >> --- >> src/mesa/drivers/common/meta_tex_subimage.c | 36 >> +++++++++++++++++++++++++++-- >> 1 file changed, 34 insertions(+), 2 deletions(-) >> >> diff --git a/src/mesa/drivers/common/meta_tex_subimage.c >> b/src/mesa/drivers/common/meta_tex_subimage.c >> index 13f8292..f4d5ac3 100644 >> --- a/src/mesa/drivers/common/meta_tex_subimage.c >> +++ b/src/mesa/drivers/common/meta_tex_subimage.c >> @@ -28,6 +28,7 @@ >> #include "blend.h" >> #include "bufferobj.h" >> #include "buffers.h" >> +#include "clear.h" >> #include "fbobject.h" >> #include "glformats.h" >> #include "glheader.h" >> @@ -278,8 +279,9 @@ _mesa_meta_pbo_GetTexSubImage(struct gl_context *ctx, >> GLuint dims, >> int full_height, image_height; >> struct gl_texture_image *pbo_tex_image; >> struct gl_renderbuffer *rb = NULL; >> - GLenum status; >> - bool success = false; >> + GLenum status, src_base_format; >> + bool success = false, clear_channels_to_zero = false; >> + float save_clear_color[4]; >> int z; >> >> if (!_mesa_is_bufferobj(packing->BufferObj)) >> @@ -380,6 +382,27 @@ _mesa_meta_pbo_GetTexSubImage(struct gl_context *ctx, >> GLuint dims, >> GL_COLOR_BUFFER_BIT, GL_NEAREST)) >> goto fail; >> >> + src_base_format = tex_image ? >> + tex_image->_BaseFormat : >> + ctx->ReadBuffer->_ColorReadBuffer->_BaseFormat; >> + >> + /* Depending on the base formats involved we might need to rebase some >> + * values. For example if we download from a Luminance format to RGBA >> + * format, we want G=0 and B=0. >> + */ >> + clear_channels_to_zero = >> + _mesa_need_luminance_to_rgb_conversion(src_base_format, >> + pbo_tex_image->_BaseFormat); >> + >> + if (clear_channels_to_zero) { >> + memcpy(save_clear_color, ctx->Color.ClearColor.f, 4 * sizeof(float)); >> + /* Clear the Green, Blue channels. */ >> + _mesa_ColorMask(GL_FALSE, GL_TRUE, GL_TRUE, >> + src_base_format != GL_LUMINANCE_ALPHA); >> + _mesa_ClearColor(0.0, 0.0, 0.0, 1.0); >> + _mesa_Clear(GL_COLOR_BUFFER_BIT); >> + } >> + >> for (z = 1; z < depth; z++) { >> _mesa_meta_bind_fbo_image(GL_READ_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, >> tex_image, zoffset + z); >> @@ -392,6 +415,15 @@ _mesa_meta_pbo_GetTexSubImage(struct gl_context *ctx, >> GLuint dims, >> 0, z * image_height, >> width, z * image_height + height, >> GL_COLOR_BUFFER_BIT, GL_NEAREST); >> + if (clear_channels_to_zero) >> + _mesa_Clear(GL_COLOR_BUFFER_BIT); >> + } >> + >> + /* Unmask the color channels and restore the saved clear color values. */ >> + if (clear_channels_to_zero) { >> + _mesa_ColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE); >> + _mesa_ClearColor(save_clear_color[0], save_clear_color[1], >> + save_clear_color[2], save_clear_color[3]); >> } >> >> success = true; > > _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
