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OPENGL: Handle GLES2 and GL shaders uniformly.

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GLES2 requires precision qualifiers to be set and allows use of precision
qualifiers. For GLES2 we define a default precision now. Since precision
qualifiers are not supported in the GLSL version we use for GL, we
introduce compatibility #defines.
This commit is contained in:
Johannes Schickel 2016-01-03 11:58:50 +01:00
parent e66e9e44d3
commit 2319fcd228
3 changed files with 28 additions and 23 deletions
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40
backends/graphics/opengl/shader.cpp
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@ -25,6 +25,7 @@
#if !USE_FORCED_GLES
#include "common/textconsole.h"
#include "common/util.h"
namespace OpenGL {
@ -44,8 +45,7 @@ const char *const g_defaultVertexShader =
"\tgl_Position = projection * position;\n"
"}\n";
#if !USE_FORCED_GLES2
const char *const g_defaultFragmentShaderGL =
const char *const g_defaultFragmentShader =
"varying vec2 texCoord;\n"
"varying vec4 blendColor;\n"
"\n"
@ -54,19 +54,24 @@ const char *const g_defaultFragmentShaderGL =
"void main(void) {\n"
"\tgl_FragColor = blendColor * texture2D(texture, texCoord);\n"
"}\n";
#endif
#if !USE_FORCED_GL
const char *const g_defaultFragmentShaderGLES2 =
"varying lowp vec2 texCoord;\n"
"varying lowp vec4 blendColor;\n"
"\n"
"uniform sampler2D texture;\n"
"\n"
"void main(void) {\n"
"\tgl_FragColor = blendColor * texture2D(texture, texCoord);\n"
"}\n";
#endif
namespace {
// Taken from: https://en.wikibooks.org/wiki/OpenGL_Programming/Modern_OpenGL_Tutorial_03#OpenGL_ES_2_portability
const char *const g_precisionDefines =
"#ifdef GL_ES\n"
"\t#if defined(GL_FRAGMENT_PRECISION_HIGH) && GL_FRAGMENT_PRECISION_HIGH == 1\n"
"\t\tprecision highp float;\n"
"\t#else\n"
"\t\tprecision mediump float;\n"
"\t#endif\n"
"#else\n"
"\t#define highp\n"
"\t#define mediump\n"
"\t#define lowp\n"
"#endif\n";
} // End of anonymous namespace
Shader::Shader(const Common::String &vertex, const Common::String &fragment)
: _vertex(vertex), _fragment(fragment), _program(0), _projectionLocation(-1), _textureLocation(-1) {
@ -188,7 +193,12 @@ GLshader Shader::compileShader(const char *source, GLenum shaderType) {
return 0;
}
GL_CALL(glShaderSource(handle, 1, &source, nullptr));
const char *const sources[2] = {
g_precisionDefines,
source
};
GL_CALL(glShaderSource(handle, ARRAYSIZE(sources), sources, nullptr));
GL_CALL(glCompileShader(handle));
GLint result;