maybe implemented sphere drawing

Author: FreehandBlock51

include/viewer/sphere.h

@@ -0,0 +1,26 @@
+#pragma once
+
+/**
+ * Utilities for rendering a sphere
+ */
+
+
+#include <gl_includes.h>
+#include <cglm/cglm.h>
+#include "sim/sphere.h"
+
+/**
+ * The minimum size required of a vertex array for a sphere
+ */
+#define CSPHERE_VERTEX_ARRAY_SIZE 49
+
+/**
+ * Creates a transformation matrix for a sphere
+ */
+void csphere_make_transform(csphere_t sphere, mat4 transform);
+
+/**
+ * Generates vertices to render a given sphere.
+ * Intended to be drawn with the sphere_* shaders
+ */
+void csphere_gen_vertices(csphere_t sphere, GLfloat vertices[CSPHERE_VERTEX_ARRAY_SIZE]);

shaders/sphere_uniform_color.fragment

@@ -0,0 +1,16 @@
+#version 330 core
+
+in vec3 in_position_relative;
+in float radius;
+
+out vec4 out_color;
+
+uniform vec4 color;
+
+void main() {
+    if (magnitude(in_position_relative) > radius) {
+        discard;
+    }
+
+    out_color = color;
+}

shaders/sphere_uniform_color.vertex

@@ -0,0 +1,27 @@
+#version 330 core
+
+layout(location=0) in struct {
+    float radius;
+    float u;
+    float v;
+} input;
+
+uniform mat4 model;
+uniform mat4 view;
+uniform mat4 projection;
+
+out vec3 out_position_relative;
+out float radius;
+
+void main() {
+    float r_current = input.radius * cos(input.u);
+    vec3 position = vec3(
+        r_current * cos(input.v),
+        r_current * sin(input.v),
+        r_current
+    );
+
+    out_position_relative = position;
+    radius = input.radius;
+    gl_Position = projection * view * model * vec4(position, 1.0f);
+}

src/viewer/sphere.c

@@ -0,0 +1,21 @@
+#include "viewer/sphere.h"
+
+#include "common/defines.h"
+
+void csphere_make_transform(csphere_t sphere, mat4 transform) {
+    glm_mat4_identity(transform);
+    glm_translate(transform, vec3_to_cglm(sphere.position));
+}
+
+void csphere_gen_vertices(csphere_t sphere, GLfloat vertices[CSPHERE_VERTEX_ARRAY_SIZE]) {
+    safe_assert(vertices != NULL,);
+
+    size_t i = 0;
+    for (float u = 0; u < 2 * GLM_PIf; u += GLM_PI_4f) {
+        for (float v = 0; v < 2 * GLM_PIf; v += GLM_PI_4f) {
+            vertices[i++] = sphere.radius;
+            vertices[i++] = u;
+            vertices[i++] = v;
+        }
+    }
+}