void OsmAnd::GPUAPI_OpenGLES2::preprocessFragmentShader(QString& code)
{
const auto& fragmentShaderAdditionalPrologue = QString::fromLatin1(
// Make some extensions required
"#ifdef GL_EXT_shader_texture_lod ""\n"
"#extension GL_EXT_shader_texture_lod : require ""\n"
"#endif // GL_EXT_shader_texture_lod ""\n"
" ""\n"
// Fragment shader output declaration
"#define FRAGMENT_COLOR_OUTPUT gl_FragColor ""\n"
" ""\n"
// It have been reported that GL_FRAGMENT_PRECISION_HIGH may not be defined in some cases
"#ifndef GL_FRAGMENT_PRECISION_HIGH ""\n"
"#if %HighPrecisionSupported% ""\n"
"#define GL_FRAGMENT_PRECISION_HIGH 1 ""\n"
"#endif ""\n"
"#endif ""\n"
" ""\n"
// Set default precisions (this should be the default, but never trust mobile drivers)
"#ifdef GL_FRAGMENT_PRECISION_HIGH ""\n"
"precision highp float; ""\n"
"precision highp int; ""\n"
"#else ""\n"
"precision highp float; ""\n"
"precision highp int; ""\n"
"#endif ""\n"
" ""\n");
auto fragmentShaderAdditionalProloguePreprocessed = fragmentShaderAdditionalPrologue;
fragmentShaderAdditionalProloguePreprocessed.replace("%HighPrecisionSupported%", QString::number(
supportedFragmentShaderPrecisionFormats.contains(GL_HIGH_FLOAT) && supportedFragmentShaderPrecisionFormats.contains(GL_HIGH_INT) ? 1 : 0));
code.prepend(fragmentShaderAdditionalProloguePreprocessed);
preprocessShader(code);
}
void OsmAnd::GPUAPI_OpenGLES2::preprocessVertexShader(QString& code)
{
const auto& vertexShaderAdditionalPrologue = QString::fromLatin1(
// Set default precisions (this should be the default, but never trust mobile drivers)
"precision highp float; ""\n"
"precision highp int; ""\n"
" ""\n");
code.prepend(vertexShaderAdditionalPrologue);
preprocessShader(code);
}
QOpenGLShaderProgram* ShaderMgr::findOrLoadShader(uint flags)
{
auto it = m_shaderCache.find(flags);
// This may also return Q_NULLPTR if the load failed.
//We wait until user explictly forces shader reload until we try again to avoid spamming errors.
if(it!=m_shaderCache.end())
return *it;
//get shader file names
QString vShaderFile = getVShaderName(flags);
QString gShaderFile = getGShaderName(flags);
QString fShaderFile = getFShaderName(flags);
qCDebug(shaderMgr)<<"Loading Scenery3d shader: flags:"<<flags<<", vs:"<<vShaderFile<<", gs:"<<gShaderFile<<", fs:"<<fShaderFile<<"";
//load shader files & preprocess
QByteArray vShader,gShader,fShader;
QOpenGLShaderProgram *prog = Q_NULLPTR;
if(preprocessShader(vShaderFile,flags,vShader) &&
preprocessShader(gShaderFile,flags,gShader) &&
preprocessShader(fShaderFile,flags,fShader)
)
{
//check if this content-hash was already created for optimization
//(so that shaders with different flags, but identical implementation use the same program)
QCryptographicHash hash(QCryptographicHash::Sha256);
hash.addData(vShader);
hash.addData(gShader);
hash.addData(fShader);
QByteArray contentHash = hash.result();
if(m_shaderContentCache.contains(contentHash))
{
#ifndef NDEBUG
//qCDebug(shaderMgr)<<"Using existing shader with content-hash"<<contentHash.toHex();
#endif
prog = m_shaderContentCache[contentHash];
}
else
{
//we have to compile the shader
prog = new QOpenGLShaderProgram();
if(!loadShader(*prog,vShader,gShader,fShader))
{
delete prog;
prog = Q_NULLPTR;
qCCritical(shaderMgr)<<"ERROR: Shader '"<<flags<<"' could not be compiled. Fix errors and reload shaders or restart program.";
}
#ifndef NDEBUG
else
{
//qCDebug(shaderMgr)<<"Shader '"<<flags<<"' created, content-hash"<<contentHash.toHex();
}
#endif
m_shaderContentCache[contentHash] = prog;
}
}
else
{
qCCritical(shaderMgr)<<"ERROR: Shader '"<<flags<<"' could not be loaded/preprocessed.";
}
//may put null in cache on fail!
m_shaderCache[flags] = prog;
return prog;
}
