Crayon: Review Simple Sprite renderer

[Protofall]

The code is a bit weird, especially with the UV cropping code. A review of it would be good (While also implementing the checks for OOB and cropping). This review will probably help address #187 #193

[Protofall]

Note to self about the Simple Sprite struct

typedef struct {
    uint32  flags;              /**< \brief TA command (vertex flags) */
    float   ax;                 /**< \brief First X coordinate */
    float   ay;                 /**< \brief First Y coordinate */
    float   az;                 /**< \brief First Z coordinate */
    float   bx;                 /**< \brief Second X coordinate */
    float   by;                 /**< \brief Second Y coordinate */
    float   bz;                 /**< \brief Second Z coordinate */
    float   cx;                 /**< \brief Third X coordinate */
    float   cy;                 /**< \brief Third Y coordinate */
    float   cz;                 /**< \brief Third Z coordinate */
    float   dx;                 /**< \brief Fourth X coordinate */
    float   dy;                 /**< \brief Fourth Y coordinate */
    uint32 dummy;               /**< \brief Dummy value */
    uint32 auv;                 /**< \brief First U/V texture coordinates */
    uint32 buv;                 /**< \brief Second U/V texture coordinates */
    uint32 cuv;                 /**< \brief Third U/V texture coordinates */
} pvr_sprite_txr_t;

We can just do float* ptr = &struct.ax; and then access offsets of that pointer to "iterate" over the struct

x-es: ptr[i * 3];`
y-es: ptr[1 + (i * 3)];
z-es: ptr[2 + (i * 3)];   // Note there is no "dz", instead you'd hit the dummy value
uv-es: uint32_t* ptr2 = &struct.auv;   // There's no "duv" and trying to access it will go outside the struct and badness

[Protofall]

• Make a pvr sprite pack U only and V only functions. Leaves other coord intact, but will override the specified coord.
• For calculating vertex and UV positions, use a similar method to enhanced, have a master UV min/max and coord min/max. I think that's why #193 happens because I was overriding the UVs on one side then using those new UVs to generate more UVs for the opposite side.
  • This in-turn will mean I won't need to have the "cropping" check on the UVs since the masters won't be modified