WebGL: return -1 for invalid uniform locations and other WebGL objects

Author: phoboslab

Source/Ejecta/EJCanvas/WebGL/EJBindingWebGLObjects.h

@@ -8,7 +8,7 @@
 }
 - (id)initWithWebGLContext:(EJBindingCanvasContextWebGL *)webglContext index:(GLuint)index;
 - (void)invalidate;
-+ (GLuint)indexFromJSValue:(JSValueRef)value;
++ (GLint)indexFromJSValue:(JSValueRef)value;
 + (EJBindingWebGLObject *)webGLObjectFromJSValue:(JSValueRef)value;
 + (JSObjectRef)createJSObjectWithContext:(JSContextRef)ctx
 	scriptView:(EJJavaScriptView *)scriptView

Source/Ejecta/EJCanvas/WebGL/EJBindingWebGLObjects.m

@@ -20,11 +20,11 @@ - (void)dealloc {
 	[super dealloc];
 }
 
-+ (GLuint)indexFromJSValue:(JSValueRef)value {
++ (GLint)indexFromJSValue:(JSValueRef)value {
 	if( !value ) { return 0; }
 
 	EJBindingWebGLObject *binding = (EJBindingWebGLObject *)JSValueGetPrivate(value);
-	return (binding && [binding isKindOfClass:[self class]]) ? binding->index : 0;
+	return (binding && [binding isKindOfClass:[self class]]) ? binding->index : -1;
 }
 
 + (EJBindingWebGLObject *)webGLObjectFromJSValue:(JSValueRef)value {

Source/Ejecta/EJCanvas/WebGL/EJCanvasContextWebGL.h

@@ -1,5 +1,8 @@
 #import "EJCanvasContext.h"
 
+#define EJ_WEBGL_DEFAULT_FRAMEBUFFER -1
+#define EJ_WEBGL_DEFAULT_RENDERBUFFER -1
+
 @class EJJavaScriptView;
 @interface EJCanvasContextWebGL : EJCanvasContext {
 	GLuint viewFrameBuffer, viewRenderBuffer;
@@ -13,8 +16,8 @@
 
 - (id)initWithScriptView:(EJJavaScriptView *)scriptView width:(short)width height:(short)height;
 - (void)resizeAuxiliaryBuffers;
-- (void)bindFramebuffer:(GLuint)framebuffer toTarget:(GLuint)target;
-- (void)bindRenderbuffer:(GLuint)framebuffer toTarget:(GLuint)target;
+- (void)bindFramebuffer:(GLint)framebuffer toTarget:(GLuint)target;
+- (void)bindRenderbuffer:(GLint)renderbuffer toTarget:(GLuint)target;
 - (void)create;
 - (void)prepare;
 - (void)clear;

Source/Ejecta/EJCanvas/WebGL/EJCanvasContextWebGL.m

@@ -119,17 +119,17 @@ - (void)clear {
 	glClearColor(c[0], c[1], c[2], c[3]);
 }
 
-- (void)bindFramebuffer:(GLuint)framebuffer toTarget:(GLuint)target {
-	if( framebuffer == 0 ) {
+- (void)bindFramebuffer:(GLint)framebuffer toTarget:(GLuint)target {
+	if( framebuffer == EJ_WEBGL_DEFAULT_FRAMEBUFFER ) {
 		framebuffer = msaaEnabled ? msaaFrameBuffer : viewFrameBuffer;
-		[self bindRenderbuffer:0 toTarget:GL_RENDERBUFFER];
+		[self bindRenderbuffer:EJ_WEBGL_DEFAULT_RENDERBUFFER toTarget:GL_RENDERBUFFER];
 	}
 	glBindFramebuffer(target, framebuffer);
 	boundFrameBuffer = framebuffer;
 }
 
-- (void)bindRenderbuffer:(GLuint)renderbuffer toTarget:(GLuint)target {
-	if( renderbuffer == 0 ) {
+- (void)bindRenderbuffer:(GLint)renderbuffer toTarget:(GLuint)target {
+	if( renderbuffer == EJ_WEBGL_DEFAULT_RENDERBUFFER ) {
 		renderbuffer = msaaEnabled ? msaaRenderBuffer : viewRenderBuffer;
 	}
 	glBindRenderbuffer(target, renderbuffer);