sample shader

sample shader

////////////////////////////////////////////////////////////////
/// Programmable Vertex Shader

#version 330 core
#extension GL_ARB_separate_shader_objects : enable // only presents for separable shader

struct pica_uniforms {
    bool b[16];
    uvec4 i[4];
    vec4 f[96];
};

bool exec_shader();

#define uniforms vs_uniforms
layout (std140) uniform vs_config {
    pica_uniforms uniforms;
}

// unused registers wouldn't be declared here
layout(location = 0) in vec4 vs_in_reg0;
layout(location = 1) in vec4 vs_in_reg1;
layout(location = 2) in vec4 vs_in_reg2;
...
layout(location = 15) in vec4 vs_in_reg15;

// N = BitCount(regs.vs.output_mask)
// "layout(location = X)" only presents for separable shader
layout(location = 0) out vec4 vs_out_attr0;
layout(location = 1) out vec4 vs_out_attr1;
layout(location = 2) out vec4 vs_out_attr2;
...
layout(location = (N-1)) out vec4 vs_out_attr(N-1);

void main() {
    // initialize all output registers
    vs_out_attr0 = vec4(0.0, 0.0, 0.0, 1.0);
    vs_out_attr1 = vec4(0.0, 0.0, 0.0, 1.0);
    vs_out_attr2 = vec4(0.0, 0.0, 0.0, 1.0);
    ...
    vs_out_attrN = vec4(0.0, 0.0, 0.0, 1.0);
    exec_shader();
}

// below are generated by decompiler
bool exec_shader() {
    ...
    // inputreg[I] is translated to vs_in_regI
    
    // outputreg[I] is translated to vs_out_attrK, where K = config.state.output_map[I]
    //    i.e. the I-th bit in regs.vs.output_mask is the K-th set bit.
    // assigment operation is omitted if outputreg[I] has no mapping
}

////////////////////////////////////////////////////////////////
/// Fixed Geometry Shader

#version 330 core
#extension GL_ARB_separate_shader_objects : enable // only presents for separable shader

layout(triangles) in;
layout(triangle_strip, max_vertices = 3) out;

// "layout(location = X)" only presents for separable shader
layout (location = 1) out vec4 primary_color;
layout (location = 2) out vec2 texcoord0;
layout (location = 3) out vec2 texcoord1;
layout (location = 4) out vec2 texcoord2;
layout (location = 5) out float texcoord0_w;
layout (location = 6) out vec4 normquat;
layout (location = 7) out vec3 view;

// only presents for separable shader
out gl_PerVertex {
    vec4 gl_Position;
    float gl_ClipDistance[2];
};

layout (std140) uniform shader_data {
    ...
}

// same layout as in vertex shader output
layout(location = 0) in vec4 vs_out_attr0;
layout(location = 1) in vec4 vs_out_attr1;
layout(location = 2) in vec4 vs_out_attr2;
...
layout(location = (N-1)) in vec4 vs_out_attr(N-1);

#define uniforms gs_uniforms
layout (std140) uniform gs_config {
    pica_uniforms uniforms;
};

struct Vertex {
    vec4 attributes[N]; // N is the same as the N in input layout
};

vec4 GetVertexQuaternion(Vertex vtx) {
    return vec4(vtx.attributes[?].?...);
}

void EmitVtx(Vertex vtx, bool quats_opposite) {
    vec4 vtx_pos = vec4(vtx.attributes[?].?...);
    gl_Position = vtx_pos;
    gl_ClipDistance[0] = -vtx_pos.z;
    gl_ClipDistance[1] = dot(clip_coef, vtx_pos);
    vec4 vtx_quat = GetVertexQuaternion(vtx);
    normquat = mix(vtx_quat, -vtx_quat, bvec4(quats_opposite));'
    vec4 vtx_color = vec4(vtx.attributes[?].?...);
    primary_color = min(abs(vtx_color), vec4(1.0));
    texcoord0 = vec2(vtx.attributes[?].?...);
    texcoord1 = vec2(vtx.attributes[?].?...);
    texcoord0_w = vtx.attributes[?].?;
    texcoord2 = vec2(vtx.attributes[?].?...);
    texcoord3 = vec3(vtx.attributes[?].?...);
    EmitVertex();
}

bool AreQuaternionsOpposite(vec4 qa, vec4 qb) {
    return (dot(qa, qb) < 0.0);
}

void EmitPrim(Vertex vtx0, Vertex vtx1, Vertex vtx2) {
    EmitVtx(vtx0, false);
    EmitVtx(vtx1, AreQuaternionsOpposite(GetVertexQuaternion(vtx0), GetVertexQuaternion(vtx1)));
    EmitVtx(vtx2, AreQuaternionsOpposite(GetVertexQuaternion(vtx0), GetVertexQuaternion(vtx2)));
    EndPrimitive();
}

void main() {
    Vertex prim_buffer[3];
    prim_buffer[0].attributes = attributes[N](vs_out_attr0[0], vs_out_attr1[0], ... vs_out_attr(N-1)[0]);
    prim_buffer[1].attributes = attributes[N](vs_out_attr0[1], vs_out_attr1[1], ... vs_out_attr(N-1)[1]);
    prim_buffer[2].attributes = attributes[N](vs_out_attr0[2], vs_out_attr1[2], ... vs_out_attr(N-1)[2]);
    EmitPrim(prim_buffer[0], prim_buffer[1], prim_buffer[2]);
}

////////////////////////////////////////////////////////////////
/// Programmable Geometry Shader

#version 330 core
#extension GL_ARB_separate_shader_objects : enable // only presents for separable shader

layout(XXX) in; // XXX depends on input register 
layout(triangle_strip, max_vertices = 30) out;

// "layout(location = X)" only presents for separable shader
layout (location = 1) out vec4 primary_color;
layout (location = 2) out vec2 texcoord0;
layout (location = 3) out vec2 texcoord1;
layout (location = 4) out vec2 texcoord2;
layout (location = 5) out float texcoord0_w;
layout (location = 6) out vec4 normquat;
layout (location = 7) out vec3 view;

// only presents for separable shader
out gl_PerVertex {
    vec4 gl_Position;
    float gl_ClipDistance[2];
};

layout (std140) uniform shader_data {
    ...
}

// same layout as in vertex shader output
layout(location = 0) in vec4 vs_out_attr0;
layout(location = 1) in vec4 vs_out_attr1;
layout(location = 2) in vec4 vs_out_attr2;
...
layout(location = (N-1)) in vec4 vs_out_attr(N-1);

#define uniforms gs_uniforms
layout (std140) uniform gs_config {
    pica_uniforms uniforms;
};

struct Vertex {
    vec4 attributes[M]; // M is BitCount(regs.gs.output_mask)
};

vec4 GetVertexQuaternion(Vertex vtx) {
    return vec4(vtx.attributes[?].?...);
}

void EmitVtx(Vertex vtx, bool quats_opposite) {
    vec4 vtx_pos = vec4(vtx.attributes[?].?...);
    gl_Position = vtx_pos;
    gl_ClipDistance[0] = -vtx_pos.z;
    gl_ClipDistance[1] = dot(clip_coef, vtx_pos);
    vec4 vtx_quat = GetVertexQuaternion(vtx);
    normquat = mix(vtx_quat, -vtx_quat, bvec4(quats_opposite));'
    vec4 vtx_color = vec4(vtx.attributes[?].?...);
    primary_color = min(abs(vtx_color), vec4(1.0));
    texcoord0 = vec2(vtx.attributes[?].?...);
    texcoord1 = vec2(vtx.attributes[?].?...);
    texcoord0_w = vtx.attributes[?].?;
    texcoord2 = vec2(vtx.attributes[?].?...);
    texcoord3 = vec3(vtx.attributes[?].?...);
    EmitVertex();
}

bool AreQuaternionsOpposite(vec4 qa, vec4 qb) {
    return (dot(qa, qb) < 0.0);
}

void EmitPrim(Vertex vtx0, Vertex vtx1, Vertex vtx2) {
    EmitVtx(vtx0, false);
    EmitVtx(vtx1, AreQuaternionsOpposite(GetVertexQuaternion(vtx0), GetVertexQuaternion(vtx1)));
    EmitVtx(vtx2, AreQuaternionsOpposite(GetVertexQuaternion(vtx0), GetVertexQuaternion(vtx2)));
    EndPrimitive();
}

Vertex output_buffer;
Vertex prim_buffer[3];
uint vertex_id = 0u;
bool prim_emit = false;
bool winding = false;

void setemit(uint vertex_id_, bool prim_emit_, bool winding_) {
    vertex_id = vertex_id_;
    prim_emit = prim_emit_;
    winding = winding_;
}

void emit() {
    prim_buffer[vertex_id] = output_buffer;

    if (prim_emit) {
        if (winding) {
            EmitPrim(prim_buffer[1], prim_buffer[0], prim_buffer[2]);
            winding = false;
        } else {
            EmitPrim(prim_buffer[0], prim_buffer[1], prim_buffer[2]);
        }
    }   
}

void main() {
    // initialize all output registers
    output_buffer.attributes[0] = vec4(0.0, 0.0, 0.0, 1.0);
    output_buffer.attributes[1] = vec4(0.0, 0.0, 0.0, 1.0);
    ...
    output_buffer.attributes[N-1] = vec4(0.0, 0.0, 0.0, 1.0);
    
    exec_shader();
}

// below are generated by decompiler
bool exec_shader() {
    ...
    // inputreg[I] is translated to vs_out_attrA[B], where
    //    A = C % N'
    //    B = C / N'
    //    N' is attributes per vertex input (usually equals to N, attributes per vertex shader output)
    //    C = config.state.input_map[I], which is generated from regs.gs.input_attribute_to_register_map
    // use vec4(0.0, 0.0, 0.0, 1.0) if inputreg[I] has no mapping
    
    // outputreg[I] is translated to output_buffer.attribute[K], where K = config.state.output_map[I]
    //    i.e. the I-th bit in regs.gs.output_mask is the K-th set bit.
    // assigment operation is omitted if outputreg[I] has no mapping
}