Add MVP projection passed through push constant

main.c

@@ -2,16 +2,56 @@
 
 #include <assert.h>
 #include <math.h>
+#include <stdio.h>
+#include <string.h>
+
+#ifndef M_PI
+#define M_PI 3.14159265358979324
+#endif
 
 static const vertex_t vertices[] = {
-	{ { -0.5, -0.5 }, { 1.0, 0.0, 0.0 } },
-	{ { 0.5, -0.5 }, { 0.0, 1.0, 0.0 } },
-	{ { 0.5, 0.5 }, { 0.0, 0.0, 1.0 } },
-	{ { -0.5, 0.5 }, { 1.0, 1.0, 1.0 } },
+	{ { -1, -1 }, { 1, 0, 0 } },
+	{ { 1, -1 }, { 0, 1, 0 } },
+	{ { 1, 1 }, { 0, 0, 1 } },
+	{ { -1, 1 }, { 1, 1, 1 } },
 };
 
 static const uint16_t indices[] = { 0, 1, 2, 2, 3, 0 };
 
+// clang-format off
+#define ID \
+	{ \
+		1, 0, 0, 0, \
+		0, 1, 0, 0, \
+		0, 0, 1, 0, \
+		0, 0, 0, 1, \
+	}
+
+#define SCALE(sf) \
+	{ \
+		sf, 0,  0,  0, \
+		0,  sf, 0,  0, \
+		0,  0,  sf, 0, \
+		0,  0,  0,  1, \
+	}
+
+#define TRANSLATE(x, y, z) \
+	{ \
+		1, 0, 0, 0, \
+		0, 1, 0, 0, \
+		0, 0, 1, 0, \
+		x, y, z, 1, \
+	}
+
+#define ROT_Y(a) \
+	{ \
+		cosf(a), 0, -sinf(a), 0, \
+		0,       1, 0,        0, \
+		sinf(a), 0, cosf(a),  0, \
+		0,       0, 0,        1, \
+	}
+// clang-format on
+
 static void
 key_callback(GLFWwindow *window, int key, int scancode, int action, int mods)
 {
@@ -27,13 +67,24 @@ key_callback(GLFWwindow *window, int key, int scancode, int action, int mods)
 	}
 }
 
+static void mul(mat4_t out, const mat4_t left, const mat4_t right)
+{
+	for (unsigned y = 0; y < 4; ++y) {
+		for (unsigned x = 0; x < 4; ++x) {
+			out[y + 4 * x] = 0;
+			for (unsigned i = 0; i < 4; ++i)
+				out[y + 4 * x] += left[y + 4 * i] * right[i + 4 * x];
+		}
+	}
+}
+
 int main()
 {
 	// Set up window
 	glfwInit();
 	glfwWindowHint(GLFW_CLIENT_API, GLFW_NO_API);
 	glfwWindowHint(GLFW_RESIZABLE, GLFW_FALSE);
-	GLFWwindow *window = glfwCreateWindow(800, 600, "Foo", nullptr, nullptr);
+	GLFWwindow *window = glfwCreateWindow(800, 800, "Foo", nullptr, nullptr);
 	assert(window);
 
 	// Register input callbacks
@@ -51,9 +102,21 @@ int main()
 	gpu_ctx_t gpu;
 	gpu_init(&gpu, &gpu_config);
 
+	mvp_t mvp = {
+		.model = SCALE(0.2),
+		.view = TRANSLATE(0, 0, 0.5),
+		.proj = ID,
+	};
+
+	const mat4_t rot = ROT_Y(M_PI / 128);
 	while (!glfwWindowShouldClose(window)) {
 		glfwPollEvents();
-		gpu_render(&gpu);
+
+		mat4_t tmp;
+		memcpy(tmp, mvp.model, sizeof(mat4_t));
+		mul(mvp.model, rot, tmp);
+
+		gpu_render(&gpu, &mvp);
 	}
 
 	// Clean up