immediate.c

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#include "internal.h"
 
void C3D_ImmDrawBegin(GPU_Primitive_t primitive)
{
    C3Di_UpdateContext();
 
    // Set primitive type
    GPUCMD_AddMaskedWrite(GPUREG_PRIMITIVE_CONFIG, 2, primitive);
    // Start a new primitive (breaks off a triangle strip/fan)
    GPUCMD_AddWrite(GPUREG_RESTART_PRIMITIVE, 1);
    // Not sure if this command is necessary
    GPUCMD_AddWrite(GPUREG_INDEXBUFFER_CONFIG, 0x80000000);
    // Enable vertex submission mode
    GPUCMD_AddMaskedWrite(GPUREG_GEOSTAGE_CONFIG2, 1, 1);
    // Enable drawing mode
    GPUCMD_AddMaskedWrite(GPUREG_START_DRAW_FUNC0, 1, 0);
    // Begin immediate-mode vertex submission
    GPUCMD_AddWrite(GPUREG_FIXEDATTRIB_INDEX, 0xF);
}
 
static inline void write24(u8* p, u32 val)
{
    p[0] = val;
    p[1] = val>>8;
    p[2] = val>>16;
}
 
void C3D_ImmSendAttrib(float x, float y, float z, float w)
{
    union
    {
        u32 packed[3];
        struct
        {
            u8 x[3];
            u8 y[3];
            u8 z[3];
            u8 w[3];
        };
    } param;
 
    // Convert the values to float24
    write24(param.x, f32tof24(x));
    write24(param.y, f32tof24(y));
    write24(param.z, f32tof24(z));
    write24(param.w, f32tof24(w));
 
    // Reverse the packed words
    u32 p = param.packed[0];
    param.packed[0] = param.packed[2];
    param.packed[2] = p;
 
    // Send the attribute
    GPUCMD_AddIncrementalWrites(GPUREG_FIXEDATTRIB_DATA0, param.packed, 3);
}
 
void C3D_ImmDrawEnd(void)
{
    // Go back to configuration mode
    GPUCMD_AddMaskedWrite(GPUREG_START_DRAW_FUNC0, 1, 1);
    // Disable vertex submission mode
    GPUCMD_AddMaskedWrite(GPUREG_GEOSTAGE_CONFIG2, 1, 0);
    // Clear the post-vertex cache
    GPUCMD_AddWrite(GPUREG_VTX_FUNC, 1);
 
    C3Di_GetContext()->flags |= C3DiF_DrawUsed;
}