From e2579374e9013d9e5248e9ec7fff359e32e4e0ac Mon Sep 17 00:00:00 2001
From: outfrost <kotlet.bahn@gmail.com>
Date: Thu, 4 Jun 2020 03:54:41 +0200
Subject: [PATCH] Some debug stuff to figure out normals and switch to flat
 shading

---
 src/engine/render.c | 34 +++++++++++++++++++++++++++++++---
 1 file changed, 31 insertions(+), 3 deletions(-)

diff --git a/src/engine/render.c b/src/engine/render.c
index bd4456b..b09f25b 100644
--- a/src/engine/render.c
+++ b/src/engine/render.c
@@ -6,7 +6,8 @@
 #include "geometry.h"
 #include "performance.h"
 
-#define RENDER_DEBUG_ 0
+#define SCENE_DEBUG_ 0
+#define RENDER_DEBUG_ 1
 
 float viewportAspectRatio = 1.0f;
 const Scene* cameraAnchor;
@@ -37,6 +38,8 @@ void initRender() {
 	glLightf(GL_LIGHT0, GL_CONSTANT_ATTENUATION, 1.0f);
 	glLightf(GL_LIGHT0, GL_LINEAR_ATTENUATION, 0.05f);
 	glLightf(GL_LIGHT0, GL_QUADRATIC_ATTENUATION, 0.005f);
+	
+	glShadeModel(GL_FLAT);
 }
 
 void renderFrame() {
@@ -68,9 +71,9 @@ static void renderScene(const Scene* scene, const Transform baseTransform) {
 	glLoadTransposeMatrixf((const GLfloat*) &transform);
 
 	glDisable(GL_LIGHTING);
-#if RENDER_DEBUG_
+#if SCENE_DEBUG_
 	drawAxes();
-#endif // RENDER_DEBUG_
+#endif // SCENE_DEBUG_
 	glEnable(GL_LIGHTING);
 
 	if (scene->solid) {
@@ -127,6 +130,12 @@ static void drawAxes() {
 	glEnd();
 }
 
+#if RENDER_DEBUG_
+static GLfloat ab(GLfloat a) {
+	return a < 0 ? -a : a;
+}
+#endif // RENDER_DEBUG_
+
 static void drawSolid(const Solid* solid) {
 	if (solid == NULL) {
 		return;
@@ -145,6 +154,25 @@ static void drawSolid(const Solid* solid) {
 		for (size_t faceIndex = 0; faceIndex < mesh.numFaces; ++faceIndex) {
 			const Face face = mesh.faces[faceIndex];
 			
+#if RENDER_DEBUG_
+			if (hasNormals) {
+				glDisable(GL_LIGHTING);
+				glDisable(GL_TEXTURE_2D);
+				glBegin(GL_LINES);
+				for (size_t i = 0; i < face.numIndices; ++i) {
+					size_t vertIndex = face.indices[i];
+					Vector3D vertex = mesh.vertices[vertIndex];
+					Vector3D normal = mesh.normals[vertIndex];
+					glColor3f(ab(normal.x), ab(normal.y), ab(normal.z));
+					glVertex3f(vertex.x, vertex.y, vertex.z);
+					glVertex3f(vertex.x + normal.x, vertex.y + normal.y, vertex.z + normal.z);
+				}
+				glEnd();
+				glEnable(GL_TEXTURE_2D);
+				glEnable(GL_LIGHTING);
+			}
+#endif // RENDER_DEBUG_
+			
 			GLenum faceMode;
 			switch (face.numIndices) {
 				case 1: faceMode = GL_POINTS; break;
-- 
2.44.0