citra/src/video_core/geometry_pipeline.cpp
2017-09-30 09:34:35 +01:00

274 lines
9.4 KiB
C++

// Copyright 2017 Citra Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#include "video_core/geometry_pipeline.h"
#include "video_core/pica_state.h"
#include "video_core/regs.h"
#include "video_core/renderer_base.h"
#include "video_core/video_core.h"
namespace Pica {
/// An attribute buffering interface for different pipeline modes
class GeometryPipelineBackend {
public:
virtual ~GeometryPipelineBackend() = default;
/// Checks if there is no incomplete data transfer
virtual bool IsEmpty() const = 0;
/// Checks if the pipeline needs a direct input from index buffer
virtual bool NeedIndexInput() const = 0;
/// Submits an index from index buffer
virtual void SubmitIndex(unsigned int val) = 0;
/**
* Submits vertex attributes
* @param input attributes of a vertex output from vertex shader
* @return if the buffer is full and the geometry shader should be invoked
*/
virtual bool SubmitVertex(const Shader::AttributeBuffer& input) = 0;
};
// In the Point mode, vertex attributes are sent to the input registers in the geometry shader unit.
// The size of vertex shader outputs and geometry shader inputs are constants. Geometry shader is
// invoked upon inputs buffer filled up by vertex shader outputs. For example, if we have a geometry
// shader that takes 6 inputs, and the vertex shader outputs 2 attributes, it would take 3 vertices
// for one geometry shader invocation.
// TODO: what happens when the input size is not divisible by the output size?
class GeometryPipeline_Point : public GeometryPipelineBackend {
public:
GeometryPipeline_Point(const Regs& regs, Shader::GSUnitState& unit) : regs(regs), unit(unit) {
ASSERT(regs.pipeline.variable_primitive == 0);
ASSERT(regs.gs.input_to_uniform == 0);
vs_output_num = regs.pipeline.vs_outmap_total_minus_1_a + 1;
size_t gs_input_num = regs.gs.max_input_attribute_index + 1;
ASSERT(gs_input_num % vs_output_num == 0);
buffer_cur = attribute_buffer.attr;
buffer_end = attribute_buffer.attr + gs_input_num;
}
bool IsEmpty() const override {
return buffer_cur == attribute_buffer.attr;
}
bool NeedIndexInput() const override {
return false;
}
void SubmitIndex(unsigned int val) override {
UNREACHABLE();
}
bool SubmitVertex(const Shader::AttributeBuffer& input) override {
buffer_cur = std::copy(input.attr, input.attr + vs_output_num, buffer_cur);
if (buffer_cur == buffer_end) {
buffer_cur = attribute_buffer.attr;
unit.LoadInput(regs.gs, attribute_buffer);
return true;
}
return false;
}
private:
const Regs& regs;
Shader::GSUnitState& unit;
Shader::AttributeBuffer attribute_buffer;
Math::Vec4<float24>* buffer_cur;
Math::Vec4<float24>* buffer_end;
unsigned int vs_output_num;
};
// In VariablePrimitive mode, vertex attributes are buffered into the uniform registers in the
// geometry shader unit. The number of vertex is variable, which is specified by the first index
// value in the batch. This mode is usually used for subdivision.
class GeometryPipeline_VariablePrimitive : public GeometryPipelineBackend {
public:
GeometryPipeline_VariablePrimitive(const Regs& regs, Shader::ShaderSetup& setup)
: regs(regs), setup(setup) {
ASSERT(regs.pipeline.variable_primitive == 1);
ASSERT(regs.gs.input_to_uniform == 1);
vs_output_num = regs.pipeline.vs_outmap_total_minus_1_a + 1;
}
bool IsEmpty() const override {
return need_index;
}
bool NeedIndexInput() const override {
return need_index;
}
void SubmitIndex(unsigned int val) override {
DEBUG_ASSERT(need_index);
// The number of vertex input is put to the uniform register
float24 vertex_num = float24::FromFloat32(static_cast<float>(val));
setup.uniforms.f[0] = Math::MakeVec(vertex_num, vertex_num, vertex_num, vertex_num);
// The second uniform register and so on are used for receiving input vertices
buffer_cur = setup.uniforms.f + 1;
main_vertex_num = regs.pipeline.variable_vertex_main_num_minus_1 + 1;
total_vertex_num = val;
need_index = false;
}
bool SubmitVertex(const Shader::AttributeBuffer& input) override {
DEBUG_ASSERT(!need_index);
if (main_vertex_num != 0) {
// For main vertices, receive all attributes
buffer_cur = std::copy(input.attr, input.attr + vs_output_num, buffer_cur);
--main_vertex_num;
} else {
// For other vertices, only receive the first attribute (usually the position)
*(buffer_cur++) = input.attr[0];
}
--total_vertex_num;
if (total_vertex_num == 0) {
need_index = true;
return true;
}
return false;
}
private:
bool need_index = true;
const Regs& regs;
Shader::ShaderSetup& setup;
unsigned int main_vertex_num;
unsigned int total_vertex_num;
Math::Vec4<float24>* buffer_cur;
unsigned int vs_output_num;
};
// In FixedPrimitive mode, vertex attributes are buffered into the uniform registers in the geometry
// shader unit. The number of vertex per shader invocation is constant. This is usually used for
// particle system.
class GeometryPipeline_FixedPrimitive : public GeometryPipelineBackend {
public:
GeometryPipeline_FixedPrimitive(const Regs& regs, Shader::ShaderSetup& setup)
: regs(regs), setup(setup) {
ASSERT(regs.pipeline.variable_primitive == 0);
ASSERT(regs.gs.input_to_uniform == 1);
vs_output_num = regs.pipeline.vs_outmap_total_minus_1_a + 1;
ASSERT(vs_output_num == regs.pipeline.gs_config.stride_minus_1 + 1);
size_t vertex_num = regs.pipeline.gs_config.fixed_vertex_num_minus_1 + 1;
buffer_cur = buffer_begin = setup.uniforms.f + regs.pipeline.gs_config.start_index;
buffer_end = buffer_begin + vs_output_num * vertex_num;
}
bool IsEmpty() const override {
return buffer_cur == buffer_begin;
}
bool NeedIndexInput() const override {
return false;
}
void SubmitIndex(unsigned int val) override {
UNREACHABLE();
}
bool SubmitVertex(const Shader::AttributeBuffer& input) override {
buffer_cur = std::copy(input.attr, input.attr + vs_output_num, buffer_cur);
if (buffer_cur == buffer_end) {
buffer_cur = buffer_begin;
return true;
}
return false;
}
private:
const Regs& regs;
Shader::ShaderSetup& setup;
Math::Vec4<float24>* buffer_begin;
Math::Vec4<float24>* buffer_cur;
Math::Vec4<float24>* buffer_end;
unsigned int vs_output_num;
};
GeometryPipeline::GeometryPipeline(State& state) : state(state) {}
GeometryPipeline::~GeometryPipeline() = default;
void GeometryPipeline::SetVertexHandler(Shader::VertexHandler vertex_handler) {
this->vertex_handler = vertex_handler;
}
void GeometryPipeline::Setup(Shader::ShaderEngine* shader_engine) {
if (!backend)
return;
this->shader_engine = shader_engine;
shader_engine->SetupBatch(state.gs, state.regs.gs.main_offset);
}
void GeometryPipeline::Reconfigure() {
ASSERT(!backend || backend->IsEmpty());
if (state.regs.pipeline.use_gs == PipelineRegs::UseGS::No) {
backend = nullptr;
return;
}
ASSERT(state.regs.pipeline.use_gs == PipelineRegs::UseGS::Yes);
// The following assumes that when geometry shader is in use, the shader unit 3 is configured as
// a geometry shader unit.
// TODO: what happens if this is not true?
ASSERT(state.regs.pipeline.gs_unit_exclusive_configuration == 1);
ASSERT(state.regs.gs.shader_mode == ShaderRegs::ShaderMode::GS);
state.gs_unit.ConfigOutput(state.regs.gs);
ASSERT(state.regs.pipeline.vs_outmap_total_minus_1_a ==
state.regs.pipeline.vs_outmap_total_minus_1_b);
switch (state.regs.pipeline.gs_config.mode) {
case PipelineRegs::GSMode::Point:
backend = std::make_unique<GeometryPipeline_Point>(state.regs, state.gs_unit);
break;
case PipelineRegs::GSMode::VariablePrimitive:
backend = std::make_unique<GeometryPipeline_VariablePrimitive>(state.regs, state.gs);
break;
case PipelineRegs::GSMode::FixedPrimitive:
backend = std::make_unique<GeometryPipeline_FixedPrimitive>(state.regs, state.gs);
break;
default:
UNREACHABLE();
}
}
bool GeometryPipeline::NeedIndexInput() const {
if (!backend)
return false;
return backend->NeedIndexInput();
}
void GeometryPipeline::SubmitIndex(unsigned int val) {
backend->SubmitIndex(val);
}
void GeometryPipeline::SubmitVertex(const Shader::AttributeBuffer& input) {
if (!backend) {
// No backend means the geometry shader is disabled, so we send the vertex shader output
// directly to the primitive assembler.
vertex_handler(input);
} else {
if (backend->SubmitVertex(input)) {
shader_engine->Run(state.gs, state.gs_unit);
// The uniform b15 is set to true after every geometry shader invocation. This is useful
// for the shader to know if this is the first invocation in a batch, if the program set
// b15 to false first.
state.gs.uniforms.b[15] = true;
}
}
}
} // namespace Pica