Move to glfw

1 files changed, 46 insertions, 24 deletions

diff --git a/ppu.c b/ppu.c
index 4246e20..2c993c9 100644
--- a/ppu.c
+++ b/ppu.c
@@ -18,7 +18,6 @@ static void ppu_sprite_shift(struct nes_state *state) {
 	}
 }
 
-
 static void ppu_reset(struct nes_state *state) {
 	struct ppu_state *ppu = &state->ppu;
 	memset(ppu, 0, sizeof(struct ppu_state));
@@ -44,11 +43,11 @@ static uint32_t ppu_resolve_ciram(struct nes_state *state, uint32_t addr) {
 
 
 static uint8_t ppu_ciram_read(struct nes_state *state, uint32_t addr) {
-	return state->ppu.ciram[ppu_resolve_ciram(state, addr)];
+	return state->ciram[ppu_resolve_ciram(state, addr)];
 }
 
 static void ppu_ciram_write(struct nes_state *state, uint32_t addr, uint8_t value) {
-	state->ppu.ciram[ppu_resolve_ciram(state, addr)] = value;
+	state->ciram[ppu_resolve_ciram(state, addr)] = value;
 }
 
 static void ppu_write_2000(struct nes_state *state, uint8_t value) {
@@ -150,7 +149,41 @@ static uint8_t ppu_read_2007(struct nes_state *state) {
 	return result;
 }
 
+#if 1
+static void ppu_evaluate_sprites(struct nes_state *state) {
+	struct ppu_state *ppu = &state->ppu;
+	uint8_t sprite_height = (ppu->reg_ctrl & 0x20) ? 16 : 8;
+	uint8_t n = 0;
+
+	uint8_t *src = ppu->oam;
+	uint8_t *dst = ppu->secondary_oam;
+	for(uint8_t i = 0; i < 64; i++) {
+		uint8_t y = src[0];
+		int32_t row = (int32_t)ppu->scanline - y;
+
+		if(row >= 0 && row < sprite_height) {
+			if(n < 8) {
+				dst[0] = src[0];
+				dst[1] = src[1];
+				dst[2] = src[2];
+				dst[3] = src[3];
+				ppu->sprite_indexes[n] = i;
+				ppu->sprite_zero_hit_possible |= (i == 0) ? 1 : 0;
+
+				dst += 4;
+				n++;
+			} else {
+				ppu->reg_status |= 0x20;
+				break;
+			}
+		}
+		src += 4;
+	}
+
+	ppu->sprite_count = n;
+}
 
+#else
 static void ppu_evaluate_sprites(struct nes_state *state) {
 	struct ppu_state *ppu = &state->ppu;
 	uint8_t sprite_height = (ppu->reg_ctrl & 0x20) ? 16 : 8;
@@ -182,6 +215,7 @@ static void ppu_evaluate_sprites(struct nes_state *state) {
 
 	ppu->sprite_count = n;
 }
+#endif
 
 static void ppu_fetch_sprite_patterns(struct nes_state *state) {
 	struct ppu_state *ppu = &state->ppu;
@@ -238,9 +272,9 @@ static void ppu_render_pixel(struct nes_state *state) {
 	uint32_t x = ppu->dot - 1;
 	uint32_t y = ppu->scanline;
 
-	if(x >= 256 || y >= 240) {
-		return;
-	}
+	// if(x >= 256 || y >= 240) {
+	// 	return;
+	// }
 
 	uint32_t bit = 0x8000 >> ppu->fine_x;
 
@@ -287,11 +321,10 @@ static void ppu_render_pixel(struct nes_state *state) {
 			final_color = ppu->palette[(bg_palette << 2) | bg_pixel];
 		}
 	}
-	assert(y*256+x <= 256*240);
 	ppu->pixels[y * 256 + x] = final_color;
 }
 
-__attribute__((flatten))
+__attribute__((hot, flatten))
 static void ppu_tick(struct nes_state *state) {
 	struct ppu_state *ppu = &state->ppu;
 
@@ -390,12 +423,6 @@ static void ppu_tick(struct nes_state *state) {
 				ppu->vram_addr = (ppu->vram_addr & ~0x7be0) | (ppu->temp_addr & 0x7be0);
 			}
 
-// if(scanline == 261 && dot >= 280 && dot <= 304) {
-// 	printf("Scroll Copy (V): SL:%d DOT:%d vram_addr=%04x temp_addr=%04x\n", scanline, dot, ppu->vram_addr, ppu->temp_addr);
-// 	ppu->vram_addr = (ppu->vram_addr & 0x041f) | (ppu->temp_addr & 0x7be0);
-// }
-
-
 			if(dot == 257 && scanline < 240) {
 				ppu_evaluate_sprites(state);
 			}
@@ -437,26 +464,21 @@ static void ppu_dma_4014(struct nes_state *state, uint8_t page) {
 	uint32_t base = page << 8;
 
 	// Add 1 or 2 idle cycles depending on current CPU cycle
-	uint8_t idle_cycles = (state->cycle & 1) ? 1 : 2;
+	uint8_t idle_cycles = (state->cycles & 1) ? 1 : 2;
 	for(uint8_t i = 0; i < idle_cycles; i++) {
-		state->cycle++;
+		state->cycles++;
 		ppu_tick(state); ppu_tick(state); ppu_tick(state);
 	}
 
 	for(uint32_t i = 0; i < 256; i++) {
 		uint32_t addr = base + i;
 
-		// First CPU cycle (read, ticks only)
-		state->cycle++;
+		state->cycles++;
 		ppu_tick(state); ppu_tick(state); ppu_tick(state);
-
-		// Perform read
 		uint8_t value = memory_read_dma(state, addr);
 
-		// Second CPU cycle (write)
-		ppu_write_2004(state, value);
-
-		state->cycle++;
+		state->cycles++;
 		ppu_tick(state); ppu_tick(state); ppu_tick(state);
+		ppu_write_2004(state, value);
 	}
 }
\ No newline at end of file