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Implement sprite limit 

Accounts for number of cycles per scanline and stops pushing objects
that go over the limit. Reversed processing from high to low priority
and drawing from low to high.
This commit is contained in:
David Guillen Fandos 2023-07-31 20:14:27 +02:00
parent 54484ff131
commit 8622c43d48
1 changed files with 29 additions and 13 deletions
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42
video.cc
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@ -83,6 +83,10 @@ typedef struct
#define tile_width_8bpp 8
#define tile_size_8bpp 64
// Sprite rendering cycles
#define REND_CYC_SCANLINE 1210
#define REND_CYC_REDUCED 954
// Generate bit mask (bits 9th and 10th) with information about the pixel
// status (1st and/or 2nd target) for later blending.
static inline u16 color_flags(u32 layer) {
@ -950,12 +954,12 @@ static void render_scanline_objs(
) {
stype *scanline = (stype*)raw_ptr;
s32 vcount = read_ioreg(REG_VCOUNT);
u32 objn;
s32 objn;
u32 objcnt = obj_priority_count[priority][vcount];
u8 *objlist = obj_priority_list[priority][vcount];
// Render all the visible objects for this priority.
for (objn = 0; objn < objcnt; objn++) {
// Render all the visible objects for this priority (back to front)
for (objn = objcnt-1; objn >= 0; objn--) {
// Objects in the list are pre-filtered and sorted in the appropriate order
u32 objoff = objlist[objn];
const t_oam *oamentry = &((t_oam*)oam_ram)[objoff];
@ -1022,14 +1026,16 @@ static void render_scanline_objs(
// Invisible objects are discarded.
static void order_obj(u32 video_mode)
{
s32 obj_num;
u32 obj_num;
u32 row;
t_oam *oam_base = (t_oam*)oam_ram;
u16 rend_cycles[160];
memset(obj_priority_count, 0, sizeof(obj_priority_count));
memset(obj_alpha_count, 0, sizeof(obj_alpha_count));
memset(rend_cycles, 0, sizeof(rend_cycles));
for(obj_num = 127; obj_num >= 0; obj_num--)
for(obj_num = 0; obj_num < 128; obj_num++)
{
t_oam *oam_ptr = &oam_base[obj_num];
u16 obj_attr0 = eswap16(oam_ptr->attr0);
@ -1070,19 +1076,26 @@ static void order_obj(u32 video_mode)
if(((obj_x + obj_width) > 0) && (obj_x < 240))
{
bool is_affine = obj_attr0 & 0x100;
// Clip Y coord and height to the 0..159 interval
u32 starty = MAX(obj_y, 0);
u32 endy = MIN(obj_y + obj_height, 160);
// Calculate needed cycles to render the sprite
u16 cyccnt = is_affine ? (10 + obj_width * 2) : obj_width;
switch (obj_mode) {
case OBJ_MOD_SEMITRAN:
for(row = starty; row < endy; row++)
{
u32 cur_cnt = obj_priority_count[obj_priority][row];
obj_priority_list[obj_priority][row][cur_cnt] = obj_num;
obj_priority_count[obj_priority][row] = cur_cnt + 1;
// Mark the row as having semi-transparent objects
obj_alpha_count[row] = 1;
if (rend_cycles[row] < REND_CYC_SCANLINE) {
u32 cur_cnt = obj_priority_count[obj_priority][row];
obj_priority_list[obj_priority][row][cur_cnt] = obj_num;
obj_priority_count[obj_priority][row] = cur_cnt + 1;
rend_cycles[row] += cyccnt;
// Mark the row as having semi-transparent objects
obj_alpha_count[row] = 1;
}
}
break;
case OBJ_MOD_WINDOW:
@ -1092,9 +1105,12 @@ static void order_obj(u32 video_mode)
// Add the object to the list.
for(row = starty; row < endy; row++)
{
u32 cur_cnt = obj_priority_count[obj_priority][row];
obj_priority_list[obj_priority][row][cur_cnt] = obj_num;
obj_priority_count[obj_priority][row] = cur_cnt + 1;
if (rend_cycles[row] < REND_CYC_SCANLINE) {
u32 cur_cnt = obj_priority_count[obj_priority][row];
obj_priority_list[obj_priority][row][cur_cnt] = obj_num;
obj_priority_count[obj_priority][row] = cur_cnt + 1;
rend_cycles[row] += cyccnt;
}
}
break;
};