From 3395f17687bfe3f32249e7d1be583a7fe77c194e Mon Sep 17 00:00:00 2001
From: Luke Benstead <kazade@gmail.com>
Date: Wed, 17 Apr 2019 16:19:03 +0100
Subject: [PATCH] Throw GL_INVALID_OPERATION if mipmaps are specified for
 non-square textures

---
 GL/framebuffer.c | 7 +++++++
 GL/texture.c     | 5 +++++
 2 files changed, 12 insertions(+)

diff --git a/GL/framebuffer.c b/GL/framebuffer.c
index cd77798..9af7575 100644
--- a/GL/framebuffer.c
+++ b/GL/framebuffer.c
@@ -206,6 +206,13 @@ void APIENTRY glGenerateMipmapEXT(GLenum target) {
 
     TextureObject* tex = _glGetBoundTexture();
 
+    if(tex->width != tex->height) {
+        fprintf(stderr, "[GL ERROR] Mipmaps cannot be supported on non-square textures\n");
+        _glKosThrowError(GL_INVALID_OPERATION, __func__);
+        _glKosPrintError();
+        return;
+    }
+
     if(!tex || !tex->data || !tex->mipmapCount) {
         _glKosThrowError(GL_INVALID_OPERATION, __func__);
         _glKosPrintError();
diff --git a/GL/texture.c b/GL/texture.c
index 62bc950..f3a1662 100644
--- a/GL/texture.c
+++ b/GL/texture.c
@@ -852,6 +852,11 @@ void APIENTRY glTexImage2D(GLenum target, GLint level, GLint internalFormat,
         _glKosThrowError(GL_INVALID_VALUE, "glTexImage2D");
     }
 
+    if(level > 0 && width != height) {
+        fprintf(stderr, "[GL ERROR] Mipmaps cannot be supported on non-square textures\n");
+        _glKosThrowError(GL_INVALID_OPERATION, __func__);
+    }
+
     if(border) {
         _glKosThrowError(GL_INVALID_VALUE, "glTexImage2D");
     }