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Add optimizing AT_LIGHT_PASS builtin to canvas shaders

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This one allows for complex shaders paired with a simple lighting shader to skip code that would otherwise be pointlessly (and wastefully) run during the light pass.
You can use `if (AT_LIGHT_PASS) , negated or not, and that will be converted to a preprocessed #if when the shader is compiled.
Depending on your game (number of items and lights), this can be a *significant* performance gain, or at least avoids relying on the driver's optimizing abilities.
This commit is contained in:
Pedro J. Estébanez
2017-06-09 19:19:43 +02:00
parent 5f98c16d59
commit 184ef18420
4 changed files with 61 additions and 7 deletions
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58
drivers/gles2/shader_compiler_gles2.cpp
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@@ -502,16 +502,31 @@ String ShaderCompilerGLES2::dump_node_code(SL::Node *p_node, int p_level, bool p
SL::ControlFlowNode *cfnode = (SL::ControlFlowNode *)p_node;
if (cfnode->flow_op == SL::FLOW_OP_IF) {
code += "if (" + dump_node_code(cfnode->statements[0], p_level) + ") {" ENDL;
code += dump_node_code(cfnode->statements[1], p_level + 1);
if (cfnode->statements.size() == 3) {
// Help lazy drivers
if (!_is_condition_preprocessable(cfnode->statements[0])) {
code += "} else {" ENDL;
code += dump_node_code(cfnode->statements[2], p_level + 1);
code += "if (" + dump_node_code(cfnode->statements[0], p_level) + ") {" ENDL;
code += dump_node_code(cfnode->statements[1], p_level + 1);
if (cfnode->statements.size() == 3) {
code += "} else {" ENDL;
code += dump_node_code(cfnode->statements[2], p_level + 1);
}
code += "}" ENDL;
} else {
code += "#if (" + dump_node_code(cfnode->statements[0], p_level) + ")" ENDL;
code += dump_node_code(cfnode->statements[1], p_level);
if (cfnode->statements.size() == 3) {
code += "#else" ENDL;
code += dump_node_code(cfnode->statements[2], p_level);
}
code += "#endif" ENDL;
}
code += "}" ENDL;
} else if (cfnode->flow_op == SL::FLOW_OP_RETURN) {
if (cfnode->statements.size()) {
@@ -649,6 +664,33 @@ String ShaderCompilerGLES2::replace_string(const StringName &p_string) {
return "_" + p_string.operator String();
}
bool ShaderCompilerGLES2::_is_condition_preprocessable(ShaderLanguage::Node *p_condition) const {
// Check if this is a "(!)variable" expression
SL::Node *maybe_variable;
if (p_condition->type == SL::Node::TYPE_OPERATOR) {
SL::OperatorNode *op = (SL::OperatorNode *)p_condition;
if (op->op != SL::OP_NOT)
return false;
maybe_variable = op->arguments[0];
} else {
maybe_variable = p_condition;
}
if (maybe_variable->type != SL::Node::TYPE_VARIABLE)
return false;
SL::VariableNode *variable = (SL::VariableNode *)maybe_variable;
// Hardcoding since it's currently the only;
// if more were added, they would be better characterized
// in the various ShaderLanguage::BuiltinsDef
if (variable->name != String("AT_LIGHT_PASS"))
return false;
return true;
}
Error ShaderCompilerGLES2::compile(const String &p_code, ShaderLanguage::ShaderType p_type, String &r_code_line, String &r_globals_line, Flags &r_flags, Map<StringName, ShaderLanguage::Uniform> *r_uniforms) {
uses_texscreen = false;
@@ -873,6 +915,7 @@ ShaderCompilerGLES2::ShaderCompilerGLES2() {
mode_replace_table[ShaderLanguage::SHADER_CANVAS_ITEM_VERTEX]["PROJECTION_MATRIX"] = "projection_matrix";
mode_replace_table[ShaderLanguage::SHADER_CANVAS_ITEM_VERTEX]["EXTRA_MATRIX"] = "extra_matrix";
mode_replace_table[ShaderLanguage::SHADER_CANVAS_ITEM_VERTEX]["TIME"] = "time";
mode_replace_table[ShaderLanguage::SHADER_CANVAS_ITEM_VERTEX]["AT_LIGHT_PASS"] = "at_light_pass";
mode_replace_table[ShaderLanguage::SHADER_CANVAS_ITEM_FRAGMENT]["POSITION"] = "(gl_FragCoord.xy)";
mode_replace_table[ShaderLanguage::SHADER_CANVAS_ITEM_FRAGMENT]["NORMAL"] = "normal";
@@ -888,6 +931,7 @@ ShaderCompilerGLES2::ShaderCompilerGLES2() {
mode_replace_table[ShaderLanguage::SHADER_CANVAS_ITEM_FRAGMENT]["SCREEN_UV"] = "screen_uv";
mode_replace_table[ShaderLanguage::SHADER_CANVAS_ITEM_FRAGMENT]["POINT_COORD"] = "gl_PointCoord";
mode_replace_table[ShaderLanguage::SHADER_CANVAS_ITEM_FRAGMENT]["TIME"] = "time";
mode_replace_table[ShaderLanguage::SHADER_CANVAS_ITEM_FRAGMENT]["AT_LIGHT_PASS"] = "at_light_pass";
mode_replace_table[ShaderLanguage::SHADER_CANVAS_ITEM_LIGHT]["POSITION"] = "(gl_FragCoord.xy)";
mode_replace_table[ShaderLanguage::SHADER_CANVAS_ITEM_LIGHT]["NORMAL"] = "normal";