Add clipped sprite rotation

examples/library_examples/graphx/sprites_rotate_clipped/.gitignore

@@ -0,0 +1,7 @@
+obj/
+bin/
+src/gfx/*.c
+src/gfx/*.h
+src/gfx/*.8xv
+.DS_Store
+convimg.yaml.lst

examples/library_examples/graphx/sprites_rotate_clipped/autotest.json

@@ -0,0 +1,29 @@
+{
+  "transfer_files":
+  [
+    "bin/DEMO.8xp"
+  ],
+  "target":
+  {
+    "name": "DEMO",
+    "isASM": true
+  },
+  "sequence":
+  [
+    "action|launch",
+    "delay|500",
+    "key|enter",
+    "delay|100",
+    "hashWait|1"
+  ],
+  "hashes":
+  {
+    "1":
+    {
+      "description": "Test program exit",
+      "start": "vram_start",
+      "size": "vram_16_size",
+      "expected_CRCs": [ "FFAF89BA", "101734A5", "9DA19F44", "A32840C8", "349F4775" ]
+    }
+  }
+}

examples/library_examples/graphx/sprites_rotate_clipped/makefile

@@ -0,0 +1,15 @@
+# ----------------------------
+# Makefile Options
+# ----------------------------
+
+NAME = DEMO
+ICON = icon.png
+DESCRIPTION = "CE C Toolchain Demo"
+COMPRESSED = NO
+
+CFLAGS = -Wall -Wextra -Oz
+CXXFLAGS = -Wall -Wextra -Oz
+
+# ----------------------------
+
+include $(shell cedev-config --makefile)

examples/library_examples/graphx/sprites_rotate_clipped/readme.md

@@ -0,0 +1,5 @@
+### Clipped Rotation Demo
+
+Demonstrates the clipped/unclipped and opaque/transparent rotated sprite routines. 
+
+![Screenshot](screenshot.png)

examples/library_examples/graphx/sprites_rotate_clipped/src/gfx/convimg.yaml

@@ -0,0 +1,23 @@
+palettes:
+  - name: global_palette
+    fixed-entries:
+      - color: {index: 0, r: 255, g: 0, b: 128}
+      - color: {index: 1, r: 255, g: 255, b: 255}
+    images: automatic
+
+converts:
+  - name: sprites
+    palette: global_palette
+    transparent-color-index: 0
+    images:
+      - star.png
+
+outputs:
+  - type: c
+    include-file: gfx.h
+    palettes:
+      - global_palette
+    converts:
+      - sprites
+
+

examples/library_examples/graphx/sprites_rotate_clipped/src/main.c

@@ -0,0 +1,85 @@
+#include <ti/getcsc.h>
+#include <graphx.h>
+#include <math.h>
+#include <time.h>
+
+/* Include the converted image data */
+#include "gfx/gfx.h"
+
+int main(void)
+{
+    /* Center of the screen */
+    const int x_center = GFX_LCD_WIDTH / 2;
+    const int y_center = GFX_LCD_HEIGHT / 2;
+
+    /* Parameters for the clipping box */
+    const int box_width  = 80;
+    const int box_height = 80;
+    const float box_pivot_radius = 20.0f;
+
+    /* The positions of the 4 sprites on the screen */
+    const int distance_from_center = 30;
+    const int pos_left   = x_center - distance_from_center - (star_width  / 2);
+    const int pos_right  = x_center + distance_from_center - (star_width  / 2);
+    const int pos_top    = y_center - distance_from_center - (star_height / 2);
+    const int pos_bottom = y_center + distance_from_center - (star_height / 2);
+
+    /* Initialize graphics drawing */
+    gfx_Begin();
+
+    /* Set the palette used by the sprites */
+    gfx_SetPalette(global_palette, sizeof_global_palette, 0);
+    gfx_SetTransparentColor(0);
+
+    /* Draw to buffer to avoid artifacts */
+    gfx_SetDrawBuffer();
+
+    /* Record the start time */
+    const clock_t start_time = clock();
+
+    /* Rotate the sprites until a key is pressed */
+    do {
+        /* Get the elasped time in seconds */
+        float time_elasped = (float)(clock() - start_time) / CLOCKS_PER_SEC;
+
+        /* Calculate the clipping region */
+        int x_offset = cosf(time_elasped) * box_pivot_radius;
+        int y_offset = sinf(time_elasped) * box_pivot_radius;
+        int box_left   = x_center - (box_width  / 2) + x_offset;
+        int box_right  = x_center + (box_width  / 2) + x_offset;
+        int box_top    = y_center - (box_height / 2) + y_offset;
+        int box_bottom = y_center + (box_height / 2) + y_offset;
+        gfx_SetClipRegion(box_left, box_top, box_right, box_bottom);
+
+        /* Draw a rectangle to indicate the clipping region */
+        gfx_SetColor(2);
+        gfx_Rectangle_NoClip(box_left - 1, box_top - 1, box_width + 2, box_height + 2);
+
+        /* Complete one rotation every 6 seconds */
+        uint8_t sprite_angle = fmodf(time_elasped * 256.0f / 6.0f, 256.0f);
+
+        /* Draws an unclipped rotated sprite */
+        gfx_RotatedSprite_NoClip(star, pos_left, pos_bottom, sprite_angle);
+
+        /* Draws a rotated sprite that is clipped to the rectangular box */
+        gfx_RotatedSprite(star, pos_right, pos_bottom, sprite_angle);
+
+        /* Draws an unclipped rotated sprite with transparency */
+        gfx_RotatedTransparentSprite_NoClip(star, pos_right, pos_top, sprite_angle);
+
+        /* Draws a rotated sprite with transparency that is clipped to the rectangular box */
+        gfx_RotatedTransparentSprite(star, pos_left, pos_top, sprite_angle);
+
+        /* Show the buffered screen */
+        gfx_BlitBuffer();
+
+        /* Clear the old drawn sprite */
+        gfx_FillScreen(1);
+
+    } while (!os_GetCSC());
+
+    /* End graphics drawing */
+    gfx_End();
+
+    return 0;
+}

examples/library_examples/graphx/sprites_rotate_scale/src/main.c

@@ -40,8 +40,8 @@ int main(void)
         /* Complete one rotation every 5 seconds */
         uint8_t rotation = fmodf(time_elasped * 256.0f / 5.0f, 256.0f);
 
-        /* Interpolates between 75% and 250% scale (64 = 100% scale) */
-        uint8_t scale = (uint8_t)cosine_interpolate(time_elasped, 48, 160);
+        /* Interpolates between 75% and 225% scale (64 = 100% scale) */
+        uint8_t scale = (uint8_t)cosine_interpolate(time_elasped, 48, 144);
 
         /* The output size of the sprite can be calculated with this formula */
         uint8_t output_size = (scale * star_width) / 64;