diff --git a/src/O3DGlide3Renderer.h b/src/O3DGlide3Renderer.h
index e0cbe90..e3e3849 100644
--- a/src/O3DGlide3Renderer.h
+++ b/src/O3DGlide3Renderer.h
@@ -28,6 +28,8 @@ OF_ASSUME_NONNULL_BEGIN
 	O3DWinAPIWindow *_winAPIWindow;
 #endif
 	GrContext_t _context;
+	OFSize _clippingWindow;
+	bool _syncsToVerticalBlank;
 }
 @end
 
diff --git a/src/O3DGlide3Renderer.m b/src/O3DGlide3Renderer.m
index c6a20ca..511ec5a 100644
--- a/src/O3DGlide3Renderer.m
+++ b/src/O3DGlide3Renderer.m
@@ -13,9 +13,15 @@
  * this file.
  */
 
+#include <assert.h>
+
 #import "O3DGlide3Renderer.h"
 #import "O3DWinAPIWindow.h"
 
+@interface O3DGlide3Renderer ()
+- (void)setState;
+@end
+
 static OFSize
 screenResolutionToSize(GrScreenResolution_t resolution)
 {
@@ -180,7 +186,27 @@ floatToScreenRefresh(float refresh)
 	return GR_REFRESH_NONE;
 }
 
+static OF_INLINE void
+translateVertices(O3DVertex *vertices, size_t count, OFSize size)
+{
+	/*
+	 * Range is -1 to 1, we add 1, so we get 0 to 2 - so we need to
+	 * multiply with half the width / height.
+	 */
+	size.width /= 2;
+	size.height /= 2;
+
+	for (size_t i = 0; i < count; i++) {
+		vertices[i].x += 1;
+		vertices[i].y += 1;
+		vertices[i].x *= size.width;
+		vertices[i].y *= size.height;
+	}
+}
+
 @implementation O3DGlide3Renderer
+@synthesize syncsToVerticalBlank = _syncsToVerticalBlank;
+
 - (instancetype)initWithOptions:
     (OFDictionary OF_GENERIC(OFString *, id) *)options
 {
@@ -297,5 +323,57 @@ floatToScreenRefresh(float refresh)
 	    GR_COLORFORMAT_RGBA, GR_ORIGIN_LOWER_LEFT, 2, 1)) == 0)
 		@throw [OFInitializationFailedException
 		    exceptionWithClass: self.class];
+
+	_clippingWindow = [resolution.firstObject sizeValue];
+
+	[self setState];
+}
+
+- (void)setState
+{
+	grVertexLayout(GR_PARAM_XY, offsetof(O3DVertex, x), GR_PARAM_ENABLE);
+	grSstOrigin(GR_ORIGIN_LOWER_LEFT);
+}
+
+- (void)beginFrame
+{
+	assert(_context != 0);
+
+	if (!grSelectContext(_context))
+		[self setState];
+
+	grBufferClear(0, 0, 0);
+}
+
+- (void)setColor: (OFColor *)color
+{
+	float values[4];
+	[color getRed: &values[0]
+		green: &values[1]
+		 blue: &values[2]
+		alpha: &values[3]];
+	for (uint_fast8_t i = 0; i < 4; i++)
+		values[i] *= 255;
+	grColorCombine(GR_COMBINE_FUNCTION_LOCAL, GR_COMBINE_FACTOR_NONE,
+	    GR_COMBINE_LOCAL_CONSTANT, GR_COMBINE_OTHER_NONE, FXFALSE);
+	grConstantColorValue((((GrColor_t)values[0]) << 24) |
+	    (((GrColor_t)values[1]) << 16) | (((GrColor_t)values[2]) << 8) |
+	    (GrColor_t)values[2]);
+}
+
+- (void)drawVertices: (OFData *)vertices_
+{
+	assert(vertices_.itemSize == sizeof(O3DVertex));
+
+	OFMutableData *vertices = [[vertices_ mutableCopy] autorelease];
+	translateVertices(vertices.mutableItems, vertices.count,
+	    _clippingWindow);
+	grDrawVertexArrayContiguous(GR_TRIANGLE_STRIP,
+	    vertices.count, vertices.mutableItems, sizeof(O3DVertex));
+}
+
+- (void)endFrame
+{
+	grBufferSwap(_syncsToVerticalBlank ? 1 : 0);
 }
 @end
diff --git a/src/O3DRenderer.h b/src/O3DRenderer.h
index 5de2758..1142e53 100644
--- a/src/O3DRenderer.h
+++ b/src/O3DRenderer.h
@@ -19,13 +19,22 @@ OF_ASSUME_NONNULL_BEGIN
 
 typedef OFPair OF_GENERIC(OFValue *, OFNumber *) *O3DResolution;
 
+typedef struct OF_BOXABLE {
+	float x, y;
+} O3DVertex;
+
 @protocol O3DRenderer <OFObject>
 @property (readonly, nonatomic) OFArray OF_GENERIC(OFPair OF_GENERIC(OFValue *,
     OFNumber *) *) *availableResolutions;
+@property (nonatomic) bool syncsToVerticalBlank;
 
 - (instancetype)initWithOptions:
     (nullable OFDictionary OF_GENERIC(OFString *, id) *)options;
 - (void)createWithResolution: (O3DResolution)resolution;
+- (void)beginFrame;
+- (void)setColor: (OFColor *)color;
+- (void)drawVertices: (OFData *)vertices;
+- (void)endFrame;
 @end
 
 #ifdef __cplusplus
diff --git a/tests/TestsAppDelegate.m b/tests/TestsAppDelegate.m
index 87fe929..ac970a8 100644
--- a/tests/TestsAppDelegate.m
+++ b/tests/TestsAppDelegate.m
@@ -39,7 +39,36 @@ OF_APPLICATION_DELEGATE(TestsAppDelegate)
 		   secondObject: [OFNumber numberWithFloat: 60]];
 	[engine.renderer createWithResolution: resolution];
 
-	[OFThread sleepForTimeInterval: 5];
+	O3DVertex values1[] = {
+		{ -1, -1 },
+		{ 0, 1 },
+		{ 1, -1 }
+	};
+	O3DVertex values2[] = {
+		{ -0.5, 0.5 },
+		{ 0, -0.5 },
+		{ 0.5, 0.5 }
+	};
+	OFData *vertices1 = [OFData
+	    dataWithItemsNoCopy: values1
+			  count: sizeof(values1) / sizeof(*values2)
+		       itemSize: sizeof(O3DVertex)
+		   freeWhenDone: false];
+	OFData *vertices2 = [OFData
+	    dataWithItemsNoCopy: values2
+			  count: sizeof(values2) / sizeof(*values2)
+		       itemSize: sizeof(O3DVertex)
+		   freeWhenDone: false];
+
+	OFDate *startDate = [OFDate date];
+	while (-startDate.timeIntervalSinceNow < 5) {
+		[engine.renderer beginFrame];
+		[engine.renderer setColor: [OFColor yellow]];
+		[engine.renderer drawVertices: vertices1];
+		[engine.renderer setColor: [OFColor red]];
+		[engine.renderer drawVertices: vertices2];
+		[engine.renderer endFrame];
+	}
 
 	[OFApplication terminate];
 }