drawElements.c

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#include "internal.h"
 
void C3D_DrawElements(GPU_Primitive_t primitive, int count, int type, const void* indices)
{
    C3D_Context* ctx = C3Di_GetContext();
    u32 pa = osConvertVirtToPhys(indices);
    u32 base = ctx->bufInfo.base_paddr;
    if (pa < base) return;
 
    C3Di_UpdateContext();
 
    // Set primitive type
    GPUCMD_AddMaskedWrite(GPUREG_PRIMITIVE_CONFIG, 2, primitive != GPU_TRIANGLES ? primitive : GPU_GEOMETRY_PRIM);
    // Start a new primitive (breaks off a triangle strip/fan)
    GPUCMD_AddWrite(GPUREG_RESTART_PRIMITIVE, 1);
    // Configure the index buffer
    GPUCMD_AddWrite(GPUREG_INDEXBUFFER_CONFIG, (pa - base) | (type << 31));
    // Number of vertices
    GPUCMD_AddWrite(GPUREG_NUMVERTICES, count);
    // First vertex
    GPUCMD_AddWrite(GPUREG_VERTEX_OFFSET, 0);
    // Enable triangle element drawing mode if necessary
    if (primitive == GPU_TRIANGLES)
    {
        GPUCMD_AddMaskedWrite(GPUREG_GEOSTAGE_CONFIG, 2, 0x100);
        GPUCMD_AddMaskedWrite(GPUREG_GEOSTAGE_CONFIG2, 2, 0x100);
    }
    // Enable drawing mode
    GPUCMD_AddMaskedWrite(GPUREG_START_DRAW_FUNC0, 1, 0);
    // Trigger element drawing
    GPUCMD_AddWrite(GPUREG_DRAWELEMENTS, 1);
    // Go back to configuration mode
    GPUCMD_AddMaskedWrite(GPUREG_START_DRAW_FUNC0, 1, 1);
    // Disable triangle element drawing mode if necessary
    if (primitive == GPU_TRIANGLES)
    {
        GPUCMD_AddMaskedWrite(GPUREG_GEOSTAGE_CONFIG, 2, 0);
        GPUCMD_AddMaskedWrite(GPUREG_GEOSTAGE_CONFIG2, 2, 0);
    }
    // Clear the post-vertex cache
    GPUCMD_AddWrite(GPUREG_VTX_FUNC, 1);
    GPUCMD_AddMaskedWrite(GPUREG_PRIMITIVE_CONFIG, 0x8, 0);
    GPUCMD_AddMaskedWrite(GPUREG_PRIMITIVE_CONFIG, 0x8, 0);
 
    C3Di_GetContext()->flags |= C3DiF_DrawUsed;
}