Submoduled added, SDL2 code added and rewritten to be runnable

shaders/triangle.frag

@@ -0,0 +1,9 @@
+#version 450
+
+layout(location = 0) in vec3 fragColor;
+
+layout(location = 0) out vec4 outColor;
+
+void main() {
+    outColor = vec4(fragColor, 1.0);
+}

shaders/triangle.vert

@@ -0,0 +1,20 @@
+#version 450
+
+layout(location = 0) out vec3 fragColor;
+
+const vec2 positions[3] = vec2[](
+    vec2(0.0, -0.5),
+    vec2(0.5, 0.5),
+    vec2(-0.5, 0.5)
+);
+
+const vec3 colors[3] = vec3[](
+    vec3(1.0, 0.0, 0.0),
+    vec3(0.0, 1.0, 0.0),
+    vec3(0.0, 0.0, 1.0)
+);
+
+void main() {
+    gl_Position = vec4(positions[gl_VertexIndex], 0.0, 1.0);
+    fragColor = colors[gl_VertexIndex];
+}