add dice

CMakeLists.txt

@@ -11,4 +11,5 @@ target_include_directories(trnr-lib INTERFACE
     ${CMAKE_CURRENT_SOURCE_DIR}/oversampling
     ${CMAKE_CURRENT_SOURCE_DIR}/synth
     ${CMAKE_CURRENT_SOURCE_DIR}/util
+    ${CMAKE_CURRENT_SOURCE_DIR}/gfx
 )

gfx/dice.h

@@ -0,0 +1,145 @@
+#pragma once
+#include <array>
+
+using namespace std;
+
+namespace trnr {
+struct point {
+	float x;
+	float y;
+};
+
+struct rect {
+	float x;
+	float y;
+	float width;
+	float height;
+};
+
+struct quad {
+	point p1, p2, p3, p4;
+};
+
+struct dice {
+	int width;
+	int height;
+	array<point, 6> border_points;
+	array<rect, 7> pips;
+	array<quad, 6> segments_left;
+};
+
+inline void dice_init(dice& d, float width, float height)
+{
+	const float shortening = 0.866f;
+
+	float face_height, dice_width;
+	face_height = dice_width = height / 2.f;
+	float mid_x = width / 2.f;
+	float face_half_height = face_height / 2.f;
+	float face_width = dice_width * shortening;
+
+	// border points
+	point b_p1 = point {mid_x, 0};
+	point b_p2 = point {mid_x + face_width, face_half_height};
+	point b_p3 = point {mid_x + face_width, face_half_height + face_height};
+	point b_p4 = point {mid_x, height};
+	point b_p5 = point {mid_x - face_width, face_half_height + face_height};
+	point b_p6 = point {mid_x - face_width, face_half_height};
+
+	d.border_points = {b_p1, b_p2, b_p3, b_p4, b_p5, b_p6};
+
+	const float padding = face_height * 0.09f;
+	const float pad_x = padding * shortening;
+	const float pad_y = padding;
+	const float padded_face_height = face_height - 2 * pad_y;
+
+	const int segments = d.segments_left.size();
+	// define the ratio between segments and gaps as 3:1
+	const int segment_parts = 3;
+	const int gap_part = 1;
+	// the number of parts per segment
+	const int parts_per_segment = segment_parts + gap_part;
+	const int parts = segments * parts_per_segment - 2; // remove last gap
+
+	const float segment_height = (padded_face_height / parts) * segment_parts;
+	const float gap_height = padded_face_height / parts;
+
+	// calculate segments of the left face
+	for (int i = 0; i < d.segments_left.size(); i++) {
+		const point base_p1 = point {mid_x - face_width + pad_x, face_half_height + pad_y};
+		const point base_p2 = point {mid_x - pad_x, face_height};
+		float seg_y = i * (segment_height + gap_height);
+		point p1 = {base_p1.x, base_p1.y + seg_y};
+		point p2 = {base_p2.x, base_p2.y + seg_y};
+		point p3 = {base_p2.x, base_p2.y + seg_y + segment_height};
+		point p4 = {base_p1.x, base_p1.y + seg_y + segment_height};
+		d.segments_left[i] = {p1, p2, p3, p4};
+	}
+
+	// calculate pip positions for top face (30-degree isometric perspective)
+	// correct center of the diamond face
+	// the diamond spans from b_p1 (top) to the middle of the left face
+	float diamond_center_x = mid_x;
+	float diamond_center_y = face_half_height / 2.0f + face_half_height / 2.0f; // move down to actual center
+
+	// for 30-degree isometric, the grid directions are:
+	float cos30 = 1.f;	// cos(30°) = √3/2 ≈ 0.866
+	float sin30 = 0.5f; // sin(30°) = 1/2
+
+	// scale the grid vectors to fit properly within the diamond
+	float grid_scale = 0.25f; // smaller scale to fit within diamond bounds
+
+	// grid vector 1: 30 degrees from horizontal (toward top-left of diamond)
+	float grid1_x = -cos30 * face_width * grid_scale;
+	float grid1_y = -sin30 * face_height * grid_scale;
+
+	// grid vector 2: -30 degrees from horizontal (toward top-right of diamond)
+	float grid2_x = cos30 * face_width * grid_scale;
+	float grid2_y = -sin30 * face_height * grid_scale;
+
+	const float pip_h = face_height * 0.1f;
+	const float pip_w = pip_h * 2 * shortening;
+
+	// position pips in the 30-degree isometric grid
+	for (int i = 0; i < 7; i++) {
+		float u = 0, v = 0; // grid coordinates
+
+		switch (i) {
+		case 0:
+			u = 0;
+			v = 0;
+			break; // center
+		case 1:
+			u = -1;
+			v = 1;
+			break; // top-left
+		case 2:
+			u = 1;
+			v = -1;
+			break; // bottom-right
+		case 3:
+			u = 1;
+			v = 1;
+			break; // top-right
+		case 4:
+			u = -1;
+			v = -1;
+			break; // bottom-left
+		case 5:
+			u = -1;
+			v = 0;
+			break; // center-left
+		case 6:
+			u = 1;
+			v = 0;
+			break; // center-right
+		}
+
+		// convert grid coordinates to world coordinates using 30-degree vectors
+		float pip_x = diamond_center_x + u * grid1_x + v * grid2_x;
+		float pip_y = diamond_center_y + u * grid1_y + v * grid2_y;
+
+		d.pips[i] = {pip_x - pip_w / 2, pip_y - pip_h / 2, pip_w, pip_h};
+	}
+}
+} // namespace trnr