fixed zelda line weirdness

.vscode/settings.json

@@ -8,6 +8,7 @@
         "profileapi.h": "c",
         "type_traits": "c",
         "xtr1common": "c",
-        "chrono": "c"
+        "chrono": "c",
+        "interrupts.h": "c"
     }
 }

include/cart.h

@@ -29,3 +29,5 @@ void cart_write(u16 address, u8 value);
 bool cart_need_save();
 bool cart_battery_load();
 bool cart_battery_save();
+
+u8 cart_get_rom_bank();

include/cpu.h

@@ -47,6 +47,8 @@ IN_PROC inst_get_processor(in_type type);
 #define CPU_FLAG_H BIT(ctx->regs.f, 5)
 #define CPU_FLAG_C BIT(ctx->regs.f, 4)
 
+cpu_context *cpu_get_context();
+
 u16 cpu_read_reg(reg_type rt);
 
 void cpu_set_reg(reg_type rt, u16 val);

include/gamepad.h

@@ -17,6 +17,7 @@ void gamepad_init();
 bool gamepad_button_sel();
 bool gamepad_dir_sel();
 void gamepad_set_sel(u8 value);
+void gamepad_int_update();
 
 gamepad_state *gamepad_get_state();
 u8 gamepad_get_output();

include/lcd.h

@@ -52,7 +52,7 @@ typedef enum {
     SS_LYC = (1 << 6)
 } stat_src;
 
-#define LCDS_STAT_INT(src) (lcd_get_context()->lcds & src)
+#define LCDS_STAT_INT(src) ((lcd_get_context()->lcds & src) == src)
 
 void lcd_init();
 

include/ppu.h

@@ -40,6 +40,7 @@ typedef struct {
     u8 map_x;
     u8 tile_y;
     u8 fifo_x;
+    u8 lo_scroll_x; 
 } pixel_fifo_context;
 
 typedef struct {
@@ -82,6 +83,7 @@ typedef struct {
     u32 target_frame_time;
     bool paused;
     bool frame;
+    bool debug;
 } ppu_context;
 
 void ppu_init();

lib/audio.c

@@ -353,14 +353,21 @@ void audio_sample_tick() {
         }
 
         if(ctx.buffer_write_index == FRAMES_PER_BUFFER) {
-            ctx.buffer_write_index = 0;
             float *data[2];
             data[0] = ctx.left_audio_buffer;
             data[1] = ctx.right_audio_buffer;
+            //long available = Pa_GetStreamWriteAvailable(stream);
+            //if(available > 0) {
+            //    if(available > FRAMES_PER_BUFFER) {
+            //        available = FRAMES_PER_BUFFER;
+            //    }
+            //    ctx.buffer_write_index -= available;
+                ctx.buffer_write_index = 0;
                 int err = Pa_WriteStream(stream, data, FRAMES_PER_BUFFER);
                 if(err != paNoError && err != paOutputUnderflowed) {
                     fprintf(stderr, "portaudio stream error\n\tError Number: %d\n\tError Message: %s\n", err, Pa_GetErrorText(err));
                 }
+            //}
         }
     }
 }

lib/cart.c

@@ -355,3 +355,7 @@ bool cart_battery_save(){
     fclose(fp);
 
 }
+
+u8 cart_get_rom_bank() {
+    return ctx.rom_bank_value;
+}

lib/cpu.c

@@ -120,3 +120,7 @@ void cpu_set_ie_register(u8 ie){
 void cpu_request_interrupt(interrupt_type t) {
     ctx.int_flags |= t;
 }
+
+cpu_context *cpu_get_context() {
+    return &ctx;
+}

lib/emu.c

@@ -93,10 +93,10 @@ int emu_run(int argc, char **argv) {
     while(!ctx.die) {
         sleep_ms(1);
         ui_handle_events();
-        if (prev_frame != ppu_get_context()->current_frame) {
+        //if (prev_frame != ppu_get_context()->current_frame) {
             ui_update();
-        }
-        prev_frame = ppu_get_context()->current_frame;
+        //}
+        //prev_frame = ppu_get_context()->current_frame;
     }
     
 

lib/gamepad.c

@@ -1,16 +1,33 @@
 #include <gamepad.h>
 #include <string.h>
+#include <interrupts.h>
 
 typedef struct {
     bool button_sel;
     bool dir_sel;
     gamepad_state controller;
+    gamepad_state prev;
 } gamepad_context;
 
 static gamepad_context ctx = {0};
 
 void gamepad_init();
 
+void gamepad_int_update(){
+    if(ctx.button_sel) {
+        if((ctx.prev.a == 1 && ctx.controller.a == 0) || (ctx.prev.b == 1 && ctx.controller.b == 0) || (ctx.prev.select == 1 && ctx.controller.select == 0) || (ctx.prev.start == 1 && ctx.controller.start == 0)) {
+            cpu_request_interrupt(IT_JOYPAD);
+            return;
+        }
+    }
+    if(ctx.dir_sel) {
+        if((ctx.prev.up == 1 && ctx.controller.up == 0) || (ctx.prev.down == 1 && ctx.controller.down == 0) || (ctx.prev.left == 1 && ctx.controller.left == 0) || (ctx.prev.right == 1 && ctx.controller.right == 0)) {
+            cpu_request_interrupt(IT_JOYPAD);
+        }
+    }
+
+}
+
 bool gamepad_button_sel(){
     return ctx.button_sel;
 }

lib/lcd.c

@@ -58,6 +58,14 @@ void lcd_write(u16 address, u8 value) {
     u8 *p = (u8 *)&ctx;
     p[offset] = value;
 
+    if(offset == 2) {
+        //printf("YScroll: %02X\n", value);
+    }
+
+    if(offset == 0xA) {
+        //printf("WinY: %02X\n", value);
+    }
+
     if(offset == 6) {
         //offset FF64
         dma_start(value);

lib/ppu.c

@@ -35,10 +35,12 @@ void ppu_init() {
     LCDS_MODE_SET(MODE_OAM);
 
     memset(ctx.oam_ram, 0, sizeof(ctx.oam_ram));
+    memset(ctx.vram, 0, sizeof(ctx.vram));
     memset(ctx.video_buffer, 0, YRES*XRES*sizeof(u32));
 }
 
 void ppu_tick() {
+    if(LCDC_LCD_ENABLE){
         ctx.line_ticks++;
 
         switch(LCDS_MODE) {
@@ -55,6 +57,7 @@ void ppu_tick() {
                 ppu_mode_hblank();
                 break;
         }
+    }
 }
 
 void ppu_oam_write(u16 address, u8 value) {

lib/ppu_pipeline.c

@@ -41,7 +41,10 @@ u32 pixel_fifo_pop() {
 u32 fetch_sprite_pixels(int bit, u32 color, u8 bg_color) {
     for (int i = 0; i < ppu_get_context()->fetched_entry_count; i++) {
         int sp_x = (ppu_get_context()->fetched_entries[i].x - 8) +
-            ((lcd_get_context()->scroll_x % 8));
+            ((ppu_get_context()->pfc.lo_scroll_x));
+        if(ppu_get_context()->rendering_window) { 
+            sp_x = (ppu_get_context()->fetched_entries[i].x - 8);
+        }
 
         if (sp_x + 8 < ppu_get_context()->pfc.fifo_x) {
             //past this pixel already
@@ -71,8 +74,8 @@ u32 fetch_sprite_pixels(int bit, u32 color, u8 bg_color) {
         }
 
         if(!bg_priority || bg_color == 0) {
-            color = (ppu_get_context()->fetched_entries[i].f_pn) ?
-                lcd_get_context()->sp2_colors[hi|lo] : lcd_get_context()->sp1_colors[hi|lo];
+            color = ((ppu_get_context()->fetched_entries[i].f_pn) ?
+                lcd_get_context()->sp2_colors[hi|lo] : lcd_get_context()->sp1_colors[hi|lo]);
 
             if(hi | lo) {
                 break;
@@ -89,7 +92,7 @@ bool pipeline_fifo_add() {
         return false;
     }
 
-    int x = ppu_get_context()->pfc.fetch_x - (8 - lcd_get_context()->scroll_x % 8);
+    int x = ppu_get_context()->pfc.fetch_x - (8 - ppu_get_context()->pfc.lo_scroll_x);
 
     for (int i=0; i<8; i++) {
         int bit = 7 - i;
@@ -101,7 +104,7 @@ bool pipeline_fifo_add() {
             color = lcd_get_context()->bg_colors[0];
         }
 
-        if(LCDC_OBJ_ENABLE) {
+        if(LCDC_OBJ_ENABLE && !ppu_get_context()->debug) {
             color = fetch_sprite_pixels(bit, color, hi | lo);
         }
 
@@ -118,7 +121,7 @@ void pipeline_load_sprite_tile() {
     oam_line_entry *le = ppu_get_context()->line_sprites;
 
     while(le) {
-        int sp_x = (le->entry.x - 8) + (lcd_get_context()->scroll_x % 8);
+        int sp_x = (le->entry.x - 8) + (ppu_get_context()->pfc.lo_scroll_x);
 
         if ((sp_x >= ppu_get_context()->pfc.fetch_x && sp_x < ppu_get_context()->pfc.fetch_x + 8) ||
             ((sp_x + 8) >= ppu_get_context()->pfc.fetch_x && (sp_x + 8) < ppu_get_context()->pfc.fetch_x + 8)) {
@@ -204,7 +207,7 @@ void pipeline_fetch() {
             if(ppu_get_context()->rendering_window){
                 ppu_get_context()->pfc.bgw_fetch_data[1] = bus_read(LCDC_BGW_DATA_AREA +
                     (ppu_get_context()->pfc.bgw_fetch_data[0] * 16) +
-                    (lcd_get_context()->ly % 8) * 2);
+                    (ppu_get_context()->window_line % 8) * 2);
             } else {
                 ppu_get_context()->pfc.bgw_fetch_data[1] = bus_read(LCDC_BGW_DATA_AREA +
                     (ppu_get_context()->pfc.bgw_fetch_data[0] * 16) +
@@ -220,7 +223,7 @@ void pipeline_fetch() {
             if(ppu_get_context()->rendering_window){
                 ppu_get_context()->pfc.bgw_fetch_data[2] = bus_read(LCDC_BGW_DATA_AREA +
                     (ppu_get_context()->pfc.bgw_fetch_data[0] * 16) + 1 +
-                    (lcd_get_context()->ly % 8) * 2);
+                    (ppu_get_context()->window_line % 8) * 2);
             } else {
                 ppu_get_context()->pfc.bgw_fetch_data[2] = bus_read(LCDC_BGW_DATA_AREA +
                     (ppu_get_context()->pfc.bgw_fetch_data[0] * 16) +
@@ -252,27 +255,47 @@ void pipeline_fifo_reset() {
     ppu_get_context()->pfc.pixel_fifo.head = 0;
 }
 
+//Rate at wich the screen interpolates between the old and new colors
+//Used to simulate the slow response time of the GB's LCD
+//A value of zero will always use the exiting screen color, while a 1 will always use the new color
+//any value in between will interpolate that percentage between the two
+#define INTERPOLATION_RATE 0.5
+
+u32 interpolate(u32 first, u32 second) {
+    u32 final = 0;
+    for(int c = 0; c < 4; c++) {
+        u8 c1 = (first >> (c*8)) & 0xFF;
+        u8 c2 = (second >> (c*8)) & 0xFF;
+        u8 cf = (u8)(((((float)c2/(float)0xFF) - ((float)c1/(float)0xFF)) * INTERPOLATION_RATE + ((float)c1/(float)0xFF)) * 0xFF);
+        final |= cf << (c*8);
+    }
+    return final;
+}
+
 void pipeline_push_pixel() {
     if (ppu_get_context()->pfc.pixel_fifo.size > 8) {
         u32 pixel_data = pixel_fifo_pop();
 
-        if(ppu_get_context()->pfc.pushed_x+7 >= lcd_get_context()->win_x && lcd_get_context()->ly >= lcd_get_context()->win_y && !ppu_get_context()->rendering_window && window_visible()) {
+        if(ppu_get_context()->pfc.line_x+7 >= lcd_get_context()->win_x && lcd_get_context()->ly >= lcd_get_context()->win_y && !ppu_get_context()->rendering_window && window_visible()) {
             ppu_get_context()->rendering_window = true;
             pipeline_fifo_reset();
             ppu_get_context()->pfc.cur_fetch_state = FS_TILE;
-            ppu_get_context()->pfc.fetch_x = 0;
-            ppu_get_context()->pfc.fifo_x = 0;
+            ppu_get_context()->pfc.fetch_x = ppu_get_context()->pfc.line_x;
+            ppu_get_context()->pfc.fifo_x = ppu_get_context()->pfc.line_x;
+            ppu_get_context()->pfc.pushed_x = ppu_get_context()->pfc.line_x;
             return;
         }
         if(ppu_get_context()->rendering_window) {
                 ppu_get_context()->video_buffer[ppu_get_context()->pfc.pushed_x +
-                    (lcd_get_context()->ly * XRES)] = pixel_data;
+                    (lcd_get_context()->ly * XRES)] = interpolate(ppu_get_context()->video_buffer[ppu_get_context()->pfc.pushed_x +
+                        (lcd_get_context()->ly * XRES)], pixel_data);
 
                 ppu_get_context()->pfc.pushed_x++;
         }else {
-            if(ppu_get_context()->pfc.line_x >= (lcd_get_context()->scroll_x % 8)) {
+            if(ppu_get_context()->pfc.line_x >= (ppu_get_context()->pfc.lo_scroll_x)) {
                 ppu_get_context()->video_buffer[ppu_get_context()->pfc.pushed_x +
-                    (lcd_get_context()->ly * XRES)] = pixel_data;
+                    (lcd_get_context()->ly * XRES)] = interpolate(ppu_get_context()->video_buffer[ppu_get_context()->pfc.pushed_x +
+                        (lcd_get_context()->ly * XRES)], pixel_data);
 
                     ppu_get_context()->pfc.pushed_x++;
             }

lib/ppu_sm.c

@@ -17,7 +17,6 @@ void increment_ly() {
 
     if(lcd_get_context()->ly == lcd_get_context()->ly_compare) {
         LCDS_LYC_SET(1);
-
         if(LCDS_STAT_INT(SS_LYC)) {
             cpu_request_interrupt(IT_LCD_STAT);
         }
@@ -95,6 +94,7 @@ void ppu_mode_oam() {
     }
 
     if(ppu_get_context()->line_ticks == 1) {
+        ppu_get_context()->pfc.lo_scroll_x = lcd_get_context()->scroll_x & 0b111;
         //read oam on the first tick only...
         ppu_get_context()->line_sprites = 0;
         ppu_get_context()->line_sprite_count = 0;
@@ -112,6 +112,7 @@ void ppu_mode_xfer() {
 
         if(LCDS_STAT_INT(SS_HBLANK)) {
             cpu_request_interrupt(IT_LCD_STAT);
+            printf("hblank!\n");
         }
         ppu_get_context()->rendering_window = false;
     }
@@ -123,7 +124,18 @@ void ppu_mode_vblank() {
 
         if(lcd_get_context()->ly >= LINES_PER_FRAME) {
             LCDS_MODE_SET(MODE_OAM);
+            if(LCDS_STAT_INT(SS_OAM)) {
+                cpu_request_interrupt(IT_LCD_STAT);
+            }
             lcd_get_context()->ly = 0;
+            if(lcd_get_context()->ly == lcd_get_context()->ly_compare) {
+                LCDS_LYC_SET(1);
+                if(LCDS_STAT_INT(SS_LYC)) {
+                    cpu_request_interrupt(IT_LCD_STAT);
+                }
+            } else {
+                LCDS_LYC_SET(0);
+            }
             ppu_get_context()->window_line = 0;
         }
 
@@ -156,6 +168,8 @@ void ppu_mode_hblank() {
 
             if(frame_time < ppu_get_context()->target_frame_time) {
                 delay((ppu_get_context()->target_frame_time - frame_time));
+            } else if(frame_time > ppu_get_context()->target_frame_time) {
+                //printf("Frame timing missed!\n");
             }
 
             while(ppu_get_context()->paused) {
@@ -182,6 +196,9 @@ void ppu_mode_hblank() {
 
         } else {
             LCDS_MODE_SET(MODE_OAM);
+            if(LCDS_STAT_INT(SS_OAM)) {
+                cpu_request_interrupt(IT_LCD_STAT);
+            }
         }
 
         ppu_get_context()->line_ticks = 0;

lib/ui.c

@@ -5,10 +5,15 @@
 #include <bus.h>
 #include <audio.h>
 #include <string.h>
+#include <lcd.h>
+#include <cpu.h>
+#include <cart.h>
 
 #include <SDL.h>
 #include <SDL_ttf.h>
 
+#define VRAM_DEBUG 0
+
 SDL_Window *sdlWindow;
 SDL_Renderer *sdlRenderer;
 SDL_Texture *sdlTexture;
@@ -40,7 +45,7 @@ void ui_init(){
                                             SDL_TEXTUREACCESS_STREAMING,
                                             SCREEN_WIDTH,
                                             SCREEN_HEIGHT);
-
+#if VRAM_DEBUG == 1
     SDL_CreateWindowAndRenderer(16 * 8 * scale, 32 * 8 * scale, 0, &sdlDebugWindow, &sdlDebugRenderer);
     debugScreen = SDL_CreateRGBSurface(0, (16 * 8 * scale) + (16 * scale),
                                             (32 * 8 * scale) + (64 * scale), 32,
@@ -56,9 +61,10 @@ void ui_init(){
     int x, y;
     SDL_GetWindowPosition(sdlWindow, &x, &y);
     SDL_SetWindowPosition(sdlDebugWindow, x+SCREEN_WIDTH, y);
+#endif
 }
 
-static unsigned long tile_colors[4] = {0xFFFFFFFF, 0xFFAAAAAA, 0xFF555555, 0xFF000000};
+static unsigned long tile_colors[4] = {0xFF9ABB1B, 0xFF8AAB19, 0xFF2F6130, 0xFF0E370F};
 
 void display_tile(SDL_Surface *surface, u16 startLocation, u16 tileNum, int x, int y) {
     SDL_Rect rc;
@@ -277,9 +283,23 @@ void ui_update() {
             break;
         }
     }
-    SDL_RenderPresent(sdlRenderer);
+    char cpu_buffer[1024];
+    sprintf_s(cpu_buffer, 1024, "PC: %04X, SP: %04X, AF: %02X%02X, BC: %02X%02X, DE: %02X%02X, HL: %02X%02X, Cart_Bank: %02d", cpu_get_context()->regs.pc, cpu_get_context()->regs.sp, cpu_get_context()->regs.a, cpu_get_context()->regs.f, cpu_get_context()->regs.b, cpu_get_context()->regs.c, cpu_get_context()->regs.d, cpu_get_context()->regs.e, cpu_get_context()->regs.h, cpu_get_context()->regs.l, cart_get_rom_bank());
+    message = TTF_RenderText_Solid(sans, cpu_buffer, text_color);
+    messageTexture = SDL_CreateTextureFromSurface(sdlRenderer, message);
+    messageRect.x = 0;
+    messageRect.y = (YRES * scale) + 10;
+    messageRect.w = 500;
+    messageRect.h = 20;
+    SDL_RenderCopy(sdlRenderer, messageTexture, NULL, &messageRect);
+    SDL_SetRenderDrawColor(sdlRenderer, 0, 255, 0, 255);
+    SDL_FreeSurface(message);
+    SDL_DestroyTexture(messageTexture);
 
+    SDL_RenderPresent(sdlRenderer);
+#if VRAM_DEBUG == 1
     update_debug_window();
+#endif
 }
 
 void ui_on_key(bool down, u32 key_code) {
@@ -305,6 +325,14 @@ void ui_on_key(bool down, u32 key_code) {
             printf("Resumed Emulation\n");
         }
     } 
+    if(key_code == SDLK_d && down == true) {
+        ppu_get_context()->debug = !ppu_get_context()->debug;
+        if(ppu_get_context()->debug) {
+            printf("PPU Debug Enabled\n");
+        } else {
+            printf("PPU Debug Disabled\n");
+        }
+    } 
     switch(key_code){
         case SDLK_z: gamepad_get_state()->b = down; break;
         case SDLK_x: gamepad_get_state()->a = down; break;
@@ -316,6 +344,7 @@ void ui_on_key(bool down, u32 key_code) {
         case SDLK_LEFT: gamepad_get_state()->left = down; break;
         case SDLK_RIGHT: gamepad_get_state()->right = down; break;
     }
+    gamepad_int_update();
 }