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OPENGL: Support GLSL based CLUT8 look up for GLES2+.

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This commit is contained in:
Johannes Schickel 2016-01-03 14:06:02 +01:00
parent bf2735cd53
commit 08553a09cf
6 changed files with 14 additions and 19 deletions
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17
backends/graphics/opengl/texture.cpp
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@ -504,9 +504,9 @@ void TextureRGB555::updateTexture() {
}
#endif // !USE_FORCED_GL
#if !USE_FORCED_GLES && !USE_FORCED_GLES2
#if !USE_FORCED_GLES
namespace {
const char *const g_lookUpFragmentShaderGL =
const char *const g_lookUpFragmentShader =
"varying vec2 texCoord;\n"
"varying vec4 blendColor;\n"
"\n"
@ -517,12 +517,17 @@ const char *const g_lookUpFragmentShaderGL =
"\n"
"void main(void) {\n"
"\tvec4 index = texture2D(texture, texCoord);\n"
"\tgl_FragColor = blendColor * texture2D(palette, vec2(index.x * adjustFactor, 0.0));\n"
"\tgl_FragColor = blendColor * texture2D(palette, vec2(index.a * adjustFactor, 0.0));\n"
"}\n";
} // End of anonymous namespace
// _clut8Texture needs 8 bits internal precision, otherwise graphics glitches
// can occur. GL_ALPHA does not have any internal precision requirements.
// However, in practice (according to fuzzie) it's 8bit. If we run into
// problems, we need to switch to GL_R8 and GL_RED, but that is only supported
// for ARB_texture_rg and GLES3+ (EXT_rexture_rg does not support GL_R8).
TextureCLUT8GPU::TextureCLUT8GPU()
: _clut8Texture(GL_R8, GL_RED, GL_UNSIGNED_BYTE),
: _clut8Texture(GL_ALPHA, GL_ALPHA, GL_UNSIGNED_BYTE),
_paletteTexture(GL_RGBA, GL_RGBA, GL_UNSIGNED_BYTE),
_glTexture(GL_RGBA, GL_RGBA, GL_UNSIGNED_BYTE),
_glFBO(0), _clut8Vertices(), _projectionMatrix(),
@ -531,7 +536,7 @@ TextureCLUT8GPU::TextureCLUT8GPU()
// Allocate space for 256 colors.
_paletteTexture.setSize(256, 1);
_lookUpShader = new Shader(g_defaultVertexShader, g_lookUpFragmentShaderGL);
_lookUpShader = new Shader(g_defaultVertexShader, g_lookUpFragmentShader);
_lookUpShader->recreate();
_paletteLocation = _lookUpShader->getUniformLocation("palette");
@ -772,6 +777,6 @@ void TextureCLUT8GPU::setupFBO() {
// Restore old FBO.
GL_CALL(glBindFramebuffer(GL_FRAMEBUFFER, oldFBO));
}
#endif // !USE_FORCED_GLES && !USE_FORCED_GLES2
#endif // !USE_FORCED_GLES
} // End of namespace OpenGL