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Fix reading pixels on little-endian systems #17

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Fix reading pixels on little-endian systems #17

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8 changes: 8 additions & 0 deletions src/CMakeLists.txt
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Original file line number Diff line number Diff line change
@@ -1,4 +1,5 @@
cmake_minimum_required(VERSION 2.8)
include (TestBigEndian)
# TODO headers as dependencies
# TODO shared/static switch CMake-style
set(libOpenVG_SOURCES
Expand Down Expand Up @@ -27,6 +28,13 @@ set(libOpenVG_HEADERS
shContext.h
)
add_definitions(-std=c99 -pedantic -DHAVE_CONFIG_H)

# Test endianness for pixel packing
TEST_BIG_ENDIAN(BIG_ENDIAN)
if(BIG_ENDIAN)
add_compile_definitions(BIG_ENDIAN)
endif()

include_directories(${OPENGL_INCLUDE_DIR})
# TODO what if OpenGL library has nonstandard location?
add_library(OpenVG SHARED ${libOpenVG_SOURCES})
Expand Down
23 changes: 18 additions & 5 deletions src/shImage.c
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Original file line number Diff line number Diff line change
Expand Up @@ -552,10 +552,7 @@ void shUpdateImageTexture(SHImage *i, VGContext *c)
glBindTexture(GL_TEXTURE_2D, i->texture);
glTexImage2D(GL_TEXTURE_2D, 0, i->fd.glintformat,
i->texwidth, i->texheight, 0,
i->fd.glformat, 0x8367/*i->fd.gltype*/, i->data); /* FIXME determine why the format is so silly */
/* short center=(i->texwidth*i->texheight)*2+2*i->texwidth;
// printf("shUpdateImageTexture: 0x%x 0x%x 0x%x\n",i->fd.glintformat,i->fd.glformat, i->fd.gltype);
// printf("shUpdateImageTexture: %d %d %d %d\n",i->data[center],i->data[center+1],i->data[center+2],i->data[center+3]); */
i->fd.glformat, i->fd.gltype, i->data);
}

/*----------------------------------------------------------
Expand Down Expand Up @@ -968,7 +965,11 @@ VG_API_CALL void vgSetPixels(VGint dx, VGint dy,
/* Setup window image format descriptor */
/* TODO: this actually depends on the target framebuffer type
if we really want the copy to be optimized */
#ifdef BIG_ENDIAN
shSetupImageFormat(VG_sRGBA_8888, &winfd);
#else
shSetupImageFormat(VG_sABGR_8888, &winfd);
#endif

/* OpenGL doesn't allow us to use random stride. We have to
manually copy the image data and write from a copy with
Expand Down Expand Up @@ -1026,7 +1027,11 @@ VG_API_CALL void vgWritePixels(const void * data, VGint dataStride,
/* Setup window image format descriptor */
/* TODO: this actually depends on the target framebuffer type
if we really want the copy to be optimized */
#ifdef BIG_ENDIAN
shSetupImageFormat(VG_sRGBA_8888, &winfd);
#else
shSetupImageFormat(VG_sABGR_8888, &winfd);
#endif

/* OpenGL doesn't allow us to use random stride. We have to
manually copy the image data and write from a copy with
Expand Down Expand Up @@ -1077,8 +1082,12 @@ VG_API_CALL void vgGetPixels(VGImage dst, VGint dx, VGint dy,
/* Setup window image format descriptor */
/* TODO: this actually depends on the target framebuffer type
if we really want the copy to be optimized */
#ifdef BIG_ENDIAN
shSetupImageFormat(VG_sRGBA_8888, &winfd);

#else
shSetupImageFormat(VG_sABGR_8888, &winfd);
#endif

/* OpenGL doesn't allow us to read to random destination
coordinates nor using random stride. We have to
read first and then manually copy to the image data */
Expand Down Expand Up @@ -1138,7 +1147,11 @@ VG_API_CALL void vgReadPixels(void * data, VGint dataStride,
/* Setup window image format descriptor */
/* TODO: this actually depends on the target framebuffer type
if we really want the copy to be optimized */
#ifdef BIG_ENDIAN
shSetupImageFormat(VG_sRGBA_8888, &winfd);
#else
shSetupImageFormat(VG_sABGR_8888, &winfd);
#endif

/* OpenGL doesn't allow random data stride. We have to
read first and then manually copy to the output buffer */
Expand Down