/* * SPDX-FileCopyrightText: 2024-2026 Zayn Otley * SPDX-License-Identifier: AGPL-3.0-or-later * See LICENSES/AGPL-3.0-or-later.txt. */ /* AROS hardware-presentation rotozoomer: guest C using Mode7 and a bitmap lock. * Keep the bitmap locked until the IE COPY blit has consumed its destination. * ============================================================================ * AROS ROTOZOOMER TUTORIAL: C and locked bitmap presentation * ============================================================================ * This program opens a 640 by 480 CUSTOMSCREEN, renders the affine mapping * into AllocMem memory, locks the screen bitmap, and copies the result to the * returned base address with the IE blitter. * * Shared affine model: * U = U0 + x*dU_col + y*dU_row * V = V0 + x*dV_col + y*dV_row * `compute_frame` builds signed 16.16 values from the lookup tables. * `render_mode7` starts the blitter and waits before the back buffer is read. * This variant keeps the bitmap locked until the COPY blit has completed. * The API variant uses WritePixelArray instead. * * The texture loader requires exactly TEX_SIZE bytes. The back buffer keeps * Mode7 writes outside the screen bitmap. The vblank poll follows the copy * and is not an atomic display swap. * ============================================================================ */ #include #include #include #include #include #include #include #include #include #define IE_TARGET_M68K 1 #include #define ie_write32(address, value) (IE_REG32(address) = (uint32_t)(value)) #define ie_read32(address) IE_REG32(address) /* Screen dimensions */ #define RENDER_W 640 #define RENDER_H 480 #define LINE_BYTES (RENDER_W * 4) #define TEX_STRIDE (256 * 4) #define TEX_SIZE (256 * 256 * 4) #define BACKBUF_SIZE (RENDER_W * RENDER_H * 4) /* Animation increments (8.8 fixed-point) */ #define ANGLE_INC 313 #define SCALE_INC 104 /* Raw key code for ESC */ #define RAWKEY_ESC 0x45 /* Sine table: 256 entries, signed 16-bit */ static const WORD sine_table[256] = { 0,6,13,19,25,31,38,44,50,56,62,68,74,80,86,92, 98,104,109,115,121,126,132,137,142,147,152,157,162,167,172,177, 181,185,190,194,198,202,206,209,213,216,220,223,226,229,231,234, 237,239,241,243,245,247,248,250,251,252,253,254,255,255,256,256, 256,256,256,255,255,254,253,252,251,250,248,247,245,243,241,239, 237,234,231,229,226,223,220,216,213,209,206,202,198,194,190,185, 181,177,172,167,162,157,152,147,142,137,132,126,121,115,109,104, 98,92,86,80,74,68,62,56,50,44,38,31,25,19,13,6, 0,-6,-13,-19,-25,-31,-38,-44,-50,-56,-62,-68,-74,-80,-86,-92, -98,-104,-109,-115,-121,-126,-132,-137,-142,-147,-152,-157,-162,-167,-172,-177, -181,-185,-190,-194,-198,-202,-206,-209,-213,-216,-220,-223,-226,-229,-231,-234, -237,-239,-241,-243,-245,-247,-248,-250,-251,-252,-253,-254,-255,-255,-256,-256, -256,-256,-256,-255,-255,-254,-253,-252,-251,-250,-248,-247,-245,-243,-241,-239, -237,-234,-231,-229,-226,-223,-220,-216,-213,-209,-206,-202,-198,-194,-190,-185, -181,-177,-172,-167,-162,-157,-152,-147,-142,-137,-132,-126,-121,-115,-109,-104, -98,-92,-86,-80,-74,-68,-62,-56,-50,-44,-38,-31,-25,-19,-13,-6 }; /* Reciprocal table: 256 entries, unsigned 16-bit */ static const UWORD recip_table[256] = { 512,505,497,490,484,477,471,464,458,453,447,441,436,431,426,421, 416,412,407,403,399,395,391,388,384,381,377,374,371,368,365,362, 359,357,354,352,350,348,345,343,342,340,338,336,335,333,332,331, 329,328,327,326,325,324,324,323,322,322,321,321,321,320,320,320, 320,320,320,320,321,321,321,322,322,323,324,324,325,326,327,328, 329,331,332,333,335,336,338,340,342,343,345,348,350,352,354,357, 359,362,365,368,371,374,377,381,384,388,391,395,399,403,407,412, 416,421,426,431,436,441,447,453,458,464,471,477,484,490,497,505, 512,520,528,536,544,553,561,571,580,589,599,610,620,631,642,653, 665,676,689,701,714,727,740,754,768,782,797,812,827,842,858,873, 889,905,922,938,955,972,988,1005,1022,1038,1055,1071,1087,1103,1119,1134, 1149,1163,1177,1190,1202,1214,1225,1235,1244,1252,1260,1266,1271,1275,1278,1279, 1280,1279,1278,1275,1271,1266,1260,1252,1244,1235,1225,1214,1202,1190,1177,1163, 1149,1134,1119,1103,1087,1071,1055,1038,1022,1005,988,972,955,938,922,905, 889,873,858,842,827,812,797,782,768,754,740,727,714,701,689,676, 665,653,642,631,620,610,599,589,580,571,561,553,544,536,528,520 }; struct Library *CyberGfxBase = NULL; /* Animation state */ static ULONG angle_accum, scale_accum; static LONG var_ca, var_sa, var_u0, var_v0; static char music_path[] = "sdk/examples/assets/music/chopper.ahx"; static void start_music(void) { ie_write32(IE_MEDIA_NAME_PTR, (ULONG)music_path); ie_write32(IE_MEDIA_SUBSONG, 0); ie_write32(IE_MEDIA_CTRL, IE_MEDIA_OP_PLAY); } static void stop_music(void) { ie_write32(IE_MEDIA_CTRL, IE_MEDIA_OP_STOP); } static void wait_vsync(void) { while (ie_read32(IE_VIDEO_STATUS) & IE_VIDEO_STATUS_VBLANK) {} /* wait for vblank end */ while (!(ie_read32(IE_VIDEO_STATUS) & IE_VIDEO_STATUS_VBLANK)) {} /* wait for vblank start */ } static void wait_blit(void) { while (ie_read32(IE_BLT_CTRL) & IE_BLT_CTRL_BUSY) {} } static void compute_frame(void) { ULONG angle_idx = (angle_accum >> 8) & 255; ULONG scale_idx = (scale_accum >> 8) & 255; LONG cos_val = sine_table[(angle_idx + 64) & 255]; LONG sin_val = sine_table[angle_idx]; LONG recip = (LONG)recip_table[scale_idx]; LONG ca = cos_val * recip; LONG sa = sin_val * recip; var_ca = ca; var_sa = sa; /* u0 = 0x800000 - CA*320 + SA*240 */ var_u0 = 0x800000 - (ca * 320) + (sa * 240); /* v0 = 0x800000 - SA*320 - CA*240 */ var_v0 = 0x800000 - (sa * 320) - (ca * 240); } static void render_mode7(APTR texture_buf, APTR back_buf) { ie_write32(IE_BLT_OP, IE_BLT_OP_MODE7); ie_write32(IE_BLT_SRC, (ULONG)texture_buf); ie_write32(IE_BLT_DST, (ULONG)back_buf); ie_write32(IE_BLT_WIDTH, RENDER_W); ie_write32(IE_BLT_HEIGHT, RENDER_H); ie_write32(IE_BLT_SRC_STRIDE, TEX_STRIDE); ie_write32(IE_BLT_DST_STRIDE, LINE_BYTES); ie_write32(IE_BLT_MODE7_TEX_W, 255); ie_write32(IE_BLT_MODE7_TEX_H, 255); ie_write32(IE_BLT_MODE7_U0, (ULONG)var_u0); ie_write32(IE_BLT_MODE7_V0, (ULONG)var_v0); ie_write32(IE_BLT_MODE7_DU_COL, (ULONG)var_ca); ie_write32(IE_BLT_MODE7_DV_COL, (ULONG)var_sa); ie_write32(IE_BLT_MODE7_DU_ROW, (ULONG)(-var_sa)); ie_write32(IE_BLT_MODE7_DV_ROW, (ULONG)var_ca); ie_write32(IE_BLT_CTRL, IE_BLT_CTRL_START); wait_blit(); } static int load_texture(APTR texture_buf) { /* Load texture from PROGDIR:rotozoomtexture_hw_c.raw */ BPTR fh = Open("PROGDIR:rotozoomtexture_hw_c.raw", MODE_OLDFILE); LONG bytes_read; if (!fh) { return 0; } bytes_read = Read(fh, texture_buf, TEX_SIZE); Close(fh); if (bytes_read != TEX_SIZE) { return 0; } return 1; } static void advance_animation(void) { angle_accum = (angle_accum + ANGLE_INC) & 0xFFFF; scale_accum = (scale_accum + SCALE_INC) & 0xFFFF; } int main(void) { struct Screen *screen = NULL; struct Window *window = NULL; APTR texture_buf = NULL, back_buf = NULL; ULONG display_id; int running = 1; /* Open cybergraphics.library */ CyberGfxBase = OpenLibrary("cybergraphics.library", 40); if (!CyberGfxBase) return 20; /* Allocate buffers */ texture_buf = AllocMem(TEX_SIZE, MEMF_ANY | MEMF_CLEAR); if (!texture_buf) goto cleanup; back_buf = AllocMem(BACKBUF_SIZE, MEMF_ANY | MEMF_CLEAR); if (!back_buf) goto cleanup; /* Load texture */ if (!load_texture(texture_buf)) goto cleanup; start_music(); /* Find best display mode */ { struct TagItem mode_tags[] = { { CYBRBIDTG_NominalWidth, RENDER_W }, { CYBRBIDTG_NominalHeight, RENDER_H }, { CYBRBIDTG_Depth, 32 }, { TAG_DONE, 0 } }; display_id = BestCModeIDTagList(mode_tags); if (display_id == (ULONG)INVALID_ID) goto cleanup; } /* Open screen */ { struct TagItem scr_tags[] = { { SA_Type, CUSTOMSCREEN }, { SA_DisplayID, display_id }, { SA_Width, RENDER_W }, { SA_Height, RENDER_H }, { SA_Depth, 32 }, { SA_Title, (IPTR)"Rotozoomer HW (C)" }, { SA_ShowTitle, FALSE }, { SA_Quiet, TRUE }, { TAG_DONE, 0 } }; screen = OpenScreenTagList(NULL, scr_tags); if (!screen) goto cleanup; } /* Open backdrop window */ { struct TagItem win_tags[] = { { WA_CustomScreen, (IPTR)screen }, { WA_Width, RENDER_W }, { WA_Height, RENDER_H }, { WA_IDCMP, IDCMP_RAWKEY }, { WA_Borderless, TRUE }, { WA_Backdrop, TRUE }, { WA_Activate, TRUE }, { TAG_DONE, 0 } }; window = OpenWindowTagList(NULL, win_tags); if (!window) goto cleanup; } /* Init animation */ angle_accum = 0; scale_accum = 0; /* Main loop */ while (running) { compute_frame(); render_mode7(texture_buf, back_buf); /* Lock bitmap, blit, unlock */ { ULONG vram_addr = 0, vram_stride = 0; struct TagItem lbmi_tags[] = { { LBMI_BASEADDRESS, (IPTR)&vram_addr }, { LBMI_BYTESPERROW, (IPTR)&vram_stride }, { TAG_DONE, 0 } }; APTR lock = LockBitMapTagList(screen->RastPort.BitMap, lbmi_tags); if (lock) { ie_write32(IE_BLT_OP, IE_BLT_OP_COPY); ie_write32(IE_BLT_SRC, (ULONG)back_buf); ie_write32(IE_BLT_DST, vram_addr); ie_write32(IE_BLT_WIDTH, RENDER_W); ie_write32(IE_BLT_HEIGHT, RENDER_H); ie_write32(IE_BLT_SRC_STRIDE, LINE_BYTES); ie_write32(IE_BLT_DST_STRIDE, vram_stride); ie_write32(IE_BLT_CTRL, IE_BLT_CTRL_START); wait_blit(); UnLockBitMap(lock); } } wait_vsync(); advance_animation(); /* Check IDCMP */ { struct IntuiMessage *msg; while ((msg = (struct IntuiMessage *)GetMsg(window->UserPort))) { ULONG cl = msg->Class; UWORD code = msg->Code; ReplyMsg((struct Message *)msg); if (cl == IDCMP_RAWKEY && code == RAWKEY_ESC) running = 0; } } } cleanup: stop_music(); if (window) CloseWindow(window); if (screen) CloseScreen(screen); if (back_buf) FreeMem(back_buf, BACKBUF_SIZE); if (texture_buf) FreeMem(texture_buf, TEX_SIZE); if (CyberGfxBase) CloseLibrary(CyberGfxBase); return 0; }