diff --git a/Windows/GEDebugger/GEDebugger.cpp b/Windows/GEDebugger/GEDebugger.cpp
index 86cf69d1b2..2b1639971f 100644
--- a/Windows/GEDebugger/GEDebugger.cpp
+++ b/Windows/GEDebugger/GEDebugger.cpp
@@ -157,16 +157,27 @@ void CGEDebugger::SetupPreviews() {
 			PrimaryPreviewHover(x, y);
 		});
 		primaryWindow->SetRightClickMenu(subMenu, [&] (int cmd) {
+			HMENU subMenu = GetSubMenu(g_hPopupMenus, POPUP_SUBMENU_ID_GEDBG_PREVIEW);
 			switch (cmd) {
+			case 0:
+				// Setup.
+				CheckMenuItem(subMenu, ID_GEDBG_ENABLE_PREVIEW, MF_BYCOMMAND | ((previewsEnabled_ & 1) ? MF_CHECKED : MF_UNCHECKED));
+				break;
 			case ID_GEDBG_EXPORT_IMAGE:
 				PreviewExport(primaryBuffer_);
 				break;
+			case ID_GEDBG_ENABLE_PREVIEW:
+				previewsEnabled_ ^= 1;
+				primaryWindow->Redraw();
 			default:
 				break;
 			}
 
 			return true;
 		});
+		primaryWindow->SetRedrawCallback([&] {
+			HandleRedraw(1);
+		});
 		primaryWindow->Clear();
 	}
 	if (secondWindow == nullptr) {
@@ -178,16 +189,27 @@ void CGEDebugger::SetupPreviews() {
 			SecondPreviewHover(x, y);
 		});
 		secondWindow->SetRightClickMenu(subMenu, [&] (int cmd) {
+			HMENU subMenu = GetSubMenu(g_hPopupMenus, POPUP_SUBMENU_ID_GEDBG_PREVIEW);
 			switch (cmd) {
+			case 0:
+				// Setup.
+				CheckMenuItem(subMenu, ID_GEDBG_ENABLE_PREVIEW, MF_BYCOMMAND | ((previewsEnabled_ & 2) ? MF_CHECKED : MF_UNCHECKED));
+				break;
 			case ID_GEDBG_EXPORT_IMAGE:
 				PreviewExport(secondBuffer_);
 				break;
+			case ID_GEDBG_ENABLE_PREVIEW:
+				previewsEnabled_ ^= 2;
+				secondWindow->Redraw();
 			default:
 				break;
 			}
 
 			return true;
 		});
+		secondWindow->SetRedrawCallback([&] {
+			HandleRedraw(2);
+		});
 		secondWindow->Clear();
 	}
 }
@@ -258,19 +280,18 @@ void CGEDebugger::UpdatePreviews() {
 		state = gpuDebug->GetGState();
 	}
 
+	updating_ = true;
 	UpdateTextureLevel(textureLevel_);
 	UpdatePrimaryPreview(state);
 	UpdateSecondPreview(state);
 
+	u32 primOp = PrimPreviewOp();
+	if (primOp != 0) {
+		UpdatePrimPreview(primOp, 3);
+	}
+
 	DisplayList list;
 	if (gpuDebug != nullptr && gpuDebug->GetCurrentDisplayList(list)) {
-		const u32 op = Memory::Read_U32(list.pc);
-		const u32 cmd = op >> 24;
-		// TODO: Bezier/spline?
-		if (cmd == GE_CMD_PRIM && !showClut_) {
-			UpdatePrimPreview(op);
-		}
-
 		displayList->setDisplayList(list);
 	}
 
@@ -282,6 +303,7 @@ void CGEDebugger::UpdatePreviews() {
 	matrices->Update();
 	lists->Update();
 	watch->Update();
+	updating_ = false;
 }
 
 u32 CGEDebugger::TexturePreviewFlags(const GPUgstate &state) {
diff --git a/Windows/GEDebugger/GEDebugger.h b/Windows/GEDebugger/GEDebugger.h
index d520931054..f47afc4236 100644
--- a/Windows/GEDebugger/GEDebugger.h
+++ b/Windows/GEDebugger/GEDebugger.h
@@ -70,8 +70,10 @@ private:
 	void UpdatePreviews();
 	void UpdatePrimaryPreview(const GPUgstate &state);
 	void UpdateSecondPreview(const GPUgstate &state);
-	void UpdatePrimPreview(u32 op);
+	u32 PrimPreviewOp();
+	void UpdatePrimPreview(u32 op, int which);
 	void CleanupPrimPreview();
+	void HandleRedraw(int which);
 	void UpdateSize(WORD width, WORD height);
 	void SavePosition();
 	void SetBreakNext(BreakNextType type);
@@ -106,6 +108,8 @@ private:
 	const GPUDebugBuffer *primaryBuffer_ = nullptr;
 	const GPUDebugBuffer *secondBuffer_ = nullptr;
 
+	bool updating_ = false;
+	int previewsEnabled_ = 3;
 	int minWidth_;
 	int minHeight_;
 };
diff --git a/Windows/GEDebugger/SimpleGLWindow.cpp b/Windows/GEDebugger/SimpleGLWindow.cpp
index cd848cb03a..f9c06b5c02 100644
--- a/Windows/GEDebugger/SimpleGLWindow.cpp
+++ b/Windows/GEDebugger/SimpleGLWindow.cpp
@@ -68,8 +68,7 @@ static const char basic_vs[] =
 	"}\n";
 
 SimpleGLWindow::SimpleGLWindow(HWND wnd)
-	: hWnd_(wnd), valid_(false), drawProgram_(nullptr), vao_(0), tex_(0), flags_(0), zoom_(false),
-	  dragging_(false), offsetX_(0), offsetY_(0), reformatBuf_(nullptr), hoverCallback_(nullptr) {
+	: hWnd_(wnd) {
 	SetWindowLongPtr(wnd, GWLP_USERDATA, (LONG_PTR) this);
 }
 
@@ -365,10 +364,23 @@ void SimpleGLWindow::GetContentSize(float &x, float &y, float &fw, float &fh) {
 void SimpleGLWindow::Redraw(bool andSwap) {
 	DrawChecker();
 
-	if (tw_ == 0 && th_ == 0) {
+	auto swapWithCallback = [andSwap, this]() {
 		if (andSwap) {
-			Swap();
+			swapped_ = false;
+			if (redrawCallback_ && !inRedrawCallback_) {
+				inRedrawCallback_ = true;
+				redrawCallback_();
+				inRedrawCallback_ = false;
+			}
+			// In case the callback swaps, don't do it twice.
+			if (!swapped_) {
+				Swap();
+			}
 		}
+	};
+
+	if (tw_ == 0 && th_ == 0) {
+		swapWithCallback();
 		return;
 	}
 
@@ -412,7 +424,7 @@ void SimpleGLWindow::Redraw(bool andSwap) {
 	glDrawElements(GL_TRIANGLE_STRIP, 4, GL_UNSIGNED_BYTE, vao_ ? 0 : indices);
 
 	if (andSwap) {
-		Swap();
+		swapWithCallback();
 	}
 }
 
@@ -423,7 +435,9 @@ void SimpleGLWindow::Clear() {
 }
 
 void SimpleGLWindow::Begin() {
-	Redraw(false);
+	if (!inRedrawCallback_) {
+		Redraw(false);
+	}
 
 	if (vao_) {
 		glBindVertexArray(0);
@@ -549,6 +563,7 @@ bool SimpleGLWindow::RightClick(int mouseX, int mouseY) {
 	POINT pt{mouseX, mouseY};
 	ClientToScreen(hWnd_, &pt);
 
+	rightClickCallback_(0);
 	int result = TrackPopupMenuEx(rightClickMenu_, TPM_RIGHTBUTTON | TPM_RETURNCMD, pt.x, pt.y, hWnd_, 0);
 	if (result != 0) {
 		rightClickCallback_(result);
diff --git a/Windows/GEDebugger/SimpleGLWindow.h b/Windows/GEDebugger/SimpleGLWindow.h
index 5b08fcb95c..8628ab5eef 100644
--- a/Windows/GEDebugger/SimpleGLWindow.h
+++ b/Windows/GEDebugger/SimpleGLWindow.h
@@ -81,6 +81,7 @@ struct SimpleGLWindow {
 	}
 
 	void Swap() {
+		swapped_ = true;
 		SwapBuffers(hDC_);
 	}
 
@@ -106,10 +107,15 @@ struct SimpleGLWindow {
 
 	void GetContentSize(float &x, float &y, float &fw, float &fh);
 
+	void SetRedrawCallback(std::function<void()> callback) {
+		redrawCallback_ = callback;
+	}
+
 	void SetHoverCallback(std::function<void(int, int)> hoverCallback) {
 		hoverCallback_ = hoverCallback;
 	}
 
+	// Called first with 0 that it's opening, then the selected item.
 	void SetRightClickMenu(HMENU menu, std::function<void(int)> callback) {
 		rightClickCallback_ = callback;
 		rightClickMenu_ = menu;
@@ -134,7 +140,7 @@ protected:
 	HWND hWnd_;
 	HDC hDC_;
 	HGLRC hGLRC_;
-	bool valid_;
+	bool valid_ = false;
 	// Width and height of the window.
 	int w_;
 	int h_;
@@ -143,25 +149,28 @@ protected:
 	int th_;
 	bool tflipped_;
 
-	GLSLProgram *drawProgram_;
-	GLuint vao_;
-	GLuint ibuf_;
-	GLuint vbuf_;
-	GLuint checker_;
-	GLuint tex_;
-	u32 flags_;
+	GLSLProgram *drawProgram_ = nullptr;
+	GLuint vao_ = 0;
+	GLuint ibuf_ = 0;
+	GLuint vbuf_ = 0;
+	GLuint checker_ = 0;
+	GLuint tex_ = 0;
+	u32 flags_ = 0;
 	// Disable shrink (toggled by double click.)
-	bool zoom_;
-	bool dragging_;
+	bool zoom_ = false;
+	bool dragging_ = false;
+	bool inRedrawCallback_ = false;
+	bool swapped_ = false;
 	int dragStartX_;
 	int dragStartY_;
 	u32 dragLastUpdate_;
 	// Offset to position the texture is drawn at.
-	int offsetX_;
-	int offsetY_;
-	u32 *reformatBuf_;
-	u32 reformatBufSize_;
+	int offsetX_ = 0;
+	int offsetY_ = 0;
+	u32 *reformatBuf_ = nullptr;
+	u32 reformatBufSize_ = 0;
 
+	std::function<void()> redrawCallback_;
 	std::function<void(int, int)> hoverCallback_;
 	std::function<void(int)> rightClickCallback_;
 	HMENU rightClickMenu_;
diff --git a/Windows/GEDebugger/VertexPreview.cpp b/Windows/GEDebugger/VertexPreview.cpp
index 75577a1a3c..1f78554d91 100644
--- a/Windows/GEDebugger/VertexPreview.cpp
+++ b/Windows/GEDebugger/VertexPreview.cpp
@@ -151,7 +151,21 @@ static void ExpandRectangles(std::vector<GPUDebugVertex> &vertices, std::vector<
 	count *= 3;
 }
 
-void CGEDebugger::UpdatePrimPreview(u32 op) {
+u32 CGEDebugger::PrimPreviewOp() {
+	DisplayList list;
+	if (gpuDebug != nullptr && gpuDebug->GetCurrentDisplayList(list)) {
+		const u32 op = Memory::Read_U32(list.pc);
+		const u32 cmd = op >> 24;
+		// TODO: Bezier/spline?
+		if (cmd == GE_CMD_PRIM && !showClut_) {
+			return op;
+		}
+	}
+
+	return 0;
+}
+
+void CGEDebugger::UpdatePrimPreview(u32 op, int which) {
 	const u32 prim_type = (op >> 16) & 0x7;
 	int count = op & 0xFFFF;
 	if (prim_type >= 7) {
@@ -162,7 +176,8 @@ void CGEDebugger::UpdatePrimPreview(u32 op) {
 		ERROR_LOG(G3D, "Invalid debugging environment, shutting down?");
 		return;
 	}
-	if (count == 0) {
+	which &= previewsEnabled_;
+	if (count == 0 || which == 0) {
 		return;
 	}
 
@@ -182,17 +197,6 @@ void CGEDebugger::UpdatePrimPreview(u32 op) {
 	float fw, fh;
 	float x, y;
 
-	primaryWindow->Begin();
-	primaryWindow->GetContentSize(x, y, fw, fh);
-
-	glEnable(GL_BLEND);
-	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
-	glBlendEquation(GL_FUNC_ADD);
-	glBindTexture(GL_TEXTURE_2D, 0);
-	glViewport((GLint)x, (GLint)y, (GLsizei)fw, (GLsizei)fh);
-	glScissor((GLint)x, (GLint)y, (GLsizei)fw, (GLsizei)fh);
-	BindPreviewProgram(previewProgram);
-
 	// TODO: Probably there's a better way and place to do this.
 	u16 minIndex = 0;
 	u16 maxIndex = count - 1;
@@ -209,124 +213,155 @@ void CGEDebugger::UpdatePrimPreview(u32 op) {
 		}
 	}
 
-	const float invTexWidth = 1.0f / gstate_c.curTextureWidth;
-	const float invTexHeight = 1.0f / gstate_c.curTextureHeight;
+	auto wrapCoord = [](float &coord) {
+		if (coord < 0.0f) {
+			coord += ceilf(-coord);
+		}
+		if (coord > 1.0f) {
+			coord -= floorf(coord);
+		}
+	};
+
+	const float invTexWidth = 1.0f / gpuDebug->GetGState().getTextureWidth(0);
+	const float invTexHeight = 1.0f / gpuDebug->GetGState().getTextureHeight(0);
+	const float invRealTexWidth = 1.0f / gstate_c.curTextureWidth;
+	const float invRealTexHeight = 1.0f / gstate_c.curTextureHeight;
+	bool clampS = gpuDebug->GetGState().isTexCoordClampedS();
+	bool clampT = gpuDebug->GetGState().isTexCoordClampedT();
 	for (u16 i = minIndex; i <= maxIndex; ++i) {
 		vertices[i].u *= invTexWidth;
 		vertices[i].v *= invTexHeight;
-		if (vertices[i].u > 1.0f || vertices[i].u < 0.0f)
-			vertices[i].u -= floor(vertices[i].u);
-		if (vertices[i].v > 1.0f || vertices[i].v < 0.0f)
-			vertices[i].v -= floor(vertices[i].v);
+		if (!clampS)
+			wrapCoord(vertices[i].u);
+		if (!clampT)
+			wrapCoord(vertices[i].v);
 	}
 
-	if (previewVao == 0 && gl_extensions.ARB_vertex_array_object) {
-		glGenVertexArrays(1, &previewVao);
-		glBindVertexArray(previewVao);
-		glEnableVertexAttribArray(previewProgram->a_position);
+	if (which & 1) {
+		primaryWindow->Begin();
+		primaryWindow->GetContentSize(x, y, fw, fh);
 
-		glGenBuffers(1, &ibuf);
-		glGenBuffers(1, &vbuf);
-		glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibuf);
-		glBindBuffer(GL_ARRAY_BUFFER, vbuf);
+		glEnable(GL_BLEND);
+		glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+		glBlendEquation(GL_FUNC_ADD);
+		glBindTexture(GL_TEXTURE_2D, 0);
+		// The surface is upside down, so vertical offsets are negated.
+		glViewport((GLint)x, (GLint)-(y + fh - primaryWindow->Height()), (GLsizei)fw, (GLsizei)fh);
+		glScissor((GLint)x, (GLint)-(y + fh - primaryWindow->Height()), (GLsizei)fw, (GLsizei)fh);
+		BindPreviewProgram(previewProgram);
 
-		glVertexAttribPointer(previewProgram->a_position, 3, GL_FLOAT, GL_FALSE, sizeof(GPUDebugVertex), (void *)(2 * sizeof(float)));
+		if (previewVao == 0 && gl_extensions.ARB_vertex_array_object) {
+			glGenVertexArrays(1, &previewVao);
+			glBindVertexArray(previewVao);
+			glEnableVertexAttribArray(previewProgram->a_position);
+
+			glGenBuffers(1, &ibuf);
+			glGenBuffers(1, &vbuf);
+			glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibuf);
+			glBindBuffer(GL_ARRAY_BUFFER, vbuf);
+
+			glVertexAttribPointer(previewProgram->a_position, 3, GL_FLOAT, GL_FALSE, sizeof(GPUDebugVertex), (void *)(2 * sizeof(float)));
+		}
+
+		if (vbuf != 0) {
+			glBindBuffer(GL_ARRAY_BUFFER, vbuf);
+			glBufferData(GL_ARRAY_BUFFER, vertices.size() * sizeof(GPUDebugVertex), vertices.data(), GL_STREAM_DRAW);
+		}
+
+		if (ibuf != 0 && !indices.empty()) {
+			glBindVertexArray(previewVao);
+			glBufferData(GL_ELEMENT_ARRAY_BUFFER, indices.size() * sizeof(u16), indices.data(), GL_STREAM_DRAW);
+		}
+
+		float scale[] = {
+			480.0f / (float)PSP_CoreParameter().renderWidth,
+			272.0f / (float)PSP_CoreParameter().renderHeight,
+		};
+
+		Matrix4x4 ortho;
+		ortho.setOrtho(-(float)gstate_c.curRTOffsetX, (primaryWindow->TexWidth() - (int)gstate_c.curRTOffsetX) * scale[0], primaryWindow->TexHeight() * scale[1], 0, -1, 1);
+		glUniformMatrix4fv(previewProgram->u_viewproj, 1, GL_FALSE, ortho.getReadPtr());
+		if (previewVao != 0) {
+			glBindVertexArray(previewVao);
+		} else {
+			glEnableVertexAttribArray(previewProgram->a_position);
+			glVertexAttribPointer(previewProgram->a_position, 3, GL_FLOAT, GL_FALSE, sizeof(GPUDebugVertex), (float *)vertices.data() + 2);
+		}
+
+		if (indices.empty()) {
+			glDrawArrays(glprim[prim], 0, count);
+		} else {
+			glDrawElements(glprim[prim], count, GL_UNSIGNED_SHORT, previewVao != 0 ? 0 : indices.data());
+		}
+
+		if (previewVao == 0) {
+			glDisableVertexAttribArray(previewProgram->a_position);
+		}
+
+		primaryWindow->End();
 	}
 
-	if (vbuf != 0) {
-		glBindBuffer(GL_ARRAY_BUFFER, vbuf);
-		glBufferData(GL_ARRAY_BUFFER, vertices.size() * sizeof(GPUDebugVertex), vertices.data(), GL_STREAM_DRAW);
+	if (which & 2) {
+		secondWindow->Begin();
+		secondWindow->GetContentSize(x, y, fw, fh);
+
+		glEnable(GL_BLEND);
+		glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+		glBlendEquation(GL_FUNC_ADD);
+		glBindTexture(GL_TEXTURE_2D, 0);
+		// The surface is upside down, so vertical offsets are flipped.
+		glViewport((GLint)x, (GLint)-(y + fh - secondWindow->Height()), (GLsizei)fw, (GLsizei)fh);
+		glScissor((GLint)x, (GLint)-(y + fh - secondWindow->Height()), (GLsizei)fw, (GLsizei)fh);
+		BindPreviewProgram(texPreviewProgram);
+
+		if (texPreviewVao == 0 && gl_extensions.ARB_vertex_array_object) {
+			glGenVertexArrays(1, &texPreviewVao);
+			glBindVertexArray(texPreviewVao);
+			glEnableVertexAttribArray(texPreviewProgram->a_position);
+
+			glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibuf);
+			glBindBuffer(GL_ARRAY_BUFFER, vbuf);
+
+			glVertexAttribPointer(texPreviewProgram->a_position, 2, GL_FLOAT, GL_FALSE, sizeof(GPUDebugVertex), 0);
+		}
+
+		// TODO: For some reason we have to re-upload the data?
+		if (vbuf != 0) {
+			glBindBuffer(GL_ARRAY_BUFFER, vbuf);
+			glBufferData(GL_ARRAY_BUFFER, vertices.size() * sizeof(GPUDebugVertex), vertices.data(), GL_STREAM_DRAW);
+		}
+
+		if (ibuf != 0 && !indices.empty()) {
+			glBindVertexArray(texPreviewVao);
+			glBufferData(GL_ELEMENT_ARRAY_BUFFER, indices.size() * sizeof(u16), indices.data(), GL_STREAM_DRAW);
+		}
+
+		Matrix4x4 ortho;
+		ortho.setOrtho(0.0f - (float)gstate_c.curTextureXOffset * invRealTexWidth, 1.0f - (float)gstate_c.curTextureXOffset * invRealTexWidth, 1.0f - (float)gstate_c.curTextureYOffset * invRealTexHeight, 0.0f - (float)gstate_c.curTextureYOffset * invRealTexHeight, -1.0f, 1.0f);
+		glUniformMatrix4fv(texPreviewProgram->u_viewproj, 1, GL_FALSE, ortho.getReadPtr());
+		if (texPreviewVao != 0) {
+			glBindVertexArray(texPreviewVao);
+			glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibuf);
+			glBindBuffer(GL_ARRAY_BUFFER, vbuf);
+			glEnableVertexAttribArray(texPreviewProgram->a_position);
+			glVertexAttribPointer(texPreviewProgram->a_position, 2, GL_FLOAT, GL_FALSE, sizeof(GPUDebugVertex), 0);
+		} else {
+			glEnableVertexAttribArray(texPreviewProgram->a_position);
+			glVertexAttribPointer(texPreviewProgram->a_position, 2, GL_FLOAT, GL_FALSE, sizeof(GPUDebugVertex), (float *)vertices.data());
+		}
+
+		if (indices.empty()) {
+			glDrawArrays(glprim[prim], 0, count);
+		} else {
+			glDrawElements(glprim[prim], count, GL_UNSIGNED_SHORT, texPreviewVao != 0 ? 0 : indices.data());
+		}
+
+		if (texPreviewVao == 0) {
+			glDisableVertexAttribArray(previewProgram->a_position);
+		}
+
+		secondWindow->End();
 	}
-
-	if (ibuf != 0 && !indices.empty()) {
-		glBindVertexArray(previewVao);
-		glBufferData(GL_ELEMENT_ARRAY_BUFFER, indices.size() * sizeof(u16), indices.data(), GL_STREAM_DRAW);
-	}
-
-	float scale[] = {
-		480.0f / (float)PSP_CoreParameter().renderWidth,
-		272.0f / (float)PSP_CoreParameter().renderHeight,
-	};
-
-	Matrix4x4 ortho;
-	ortho.setOrtho(-(float)gstate_c.curRTOffsetX, (primaryWindow->TexWidth() - (int)gstate_c.curRTOffsetX) * scale[0], primaryWindow->TexHeight() * scale[1], 0, -1, 1);
-	glUniformMatrix4fv(previewProgram->u_viewproj, 1, GL_FALSE, ortho.getReadPtr());
-	if (previewVao != 0) {
-		glBindVertexArray(previewVao);
-	} else {
-		glEnableVertexAttribArray(previewProgram->a_position);
-		glVertexAttribPointer(previewProgram->a_position, 3, GL_FLOAT, GL_FALSE, sizeof(GPUDebugVertex), (float *)vertices.data() + 2);
-	}
-
-	if (indices.empty()) {
-		glDrawArrays(glprim[prim], 0, count);
-	} else {
-		glDrawElements(glprim[prim], count, GL_UNSIGNED_SHORT, previewVao != 0 ? 0 : indices.data());
-	}
-
-	if (previewVao == 0) {
-		glDisableVertexAttribArray(previewProgram->a_position);
-	}
-
-	primaryWindow->End();
-
-	secondWindow->Begin();
-	secondWindow->GetContentSize(x, y, fw, fh);
-
-	glEnable(GL_BLEND);
-	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
-	glBlendEquation(GL_FUNC_ADD);
-	glBindTexture(GL_TEXTURE_2D, 0);
-	glViewport((GLint)x, (GLint)y, (GLsizei)fw, (GLsizei)fh);
-	glScissor((GLint)x, (GLint)y, (GLsizei)fw, (GLsizei)fh);
-	BindPreviewProgram(texPreviewProgram);
-
-	if (texPreviewVao == 0 && gl_extensions.ARB_vertex_array_object) {
-		glGenVertexArrays(1, &texPreviewVao);
-		glBindVertexArray(texPreviewVao);
-		glEnableVertexAttribArray(texPreviewProgram->a_position);
-
-		glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibuf);
-		glBindBuffer(GL_ARRAY_BUFFER, vbuf);
-
-		glVertexAttribPointer(texPreviewProgram->a_position, 2, GL_FLOAT, GL_FALSE, sizeof(GPUDebugVertex), 0);
-	}
-
-	// TODO: For some reason we have to re-upload the data?
-	if (vbuf != 0) {
-		glBindBuffer(GL_ARRAY_BUFFER, vbuf);
-		glBufferData(GL_ARRAY_BUFFER, vertices.size() * sizeof(GPUDebugVertex), vertices.data(), GL_STREAM_DRAW);
-	}
-
-	if (ibuf != 0 && !indices.empty()) {
-		glBindVertexArray(texPreviewVao);
-		glBufferData(GL_ELEMENT_ARRAY_BUFFER, indices.size() * sizeof(u16), indices.data(), GL_STREAM_DRAW);
-	}
-
-	ortho.setOrtho(0.0f - (float)gstate_c.curTextureXOffset * invTexWidth, 1.0f - (float)gstate_c.curTextureXOffset * invTexWidth, 1.0f - (float)gstate_c.curTextureYOffset * invTexHeight, 0.0f - (float)gstate_c.curTextureYOffset * invTexHeight, -1.0f, 1.0f);
-	glUniformMatrix4fv(texPreviewProgram->u_viewproj, 1, GL_FALSE, ortho.getReadPtr());
-	if (texPreviewVao != 0) {
-		glBindVertexArray(texPreviewVao);
-		glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibuf);
-		glBindBuffer(GL_ARRAY_BUFFER, vbuf);
-		glEnableVertexAttribArray(texPreviewProgram->a_position);
-		glVertexAttribPointer(texPreviewProgram->a_position, 2, GL_FLOAT, GL_FALSE, sizeof(GPUDebugVertex), 0);
-	} else {
-		glEnableVertexAttribArray(texPreviewProgram->a_position);
-		glVertexAttribPointer(texPreviewProgram->a_position, 2, GL_FLOAT, GL_FALSE, sizeof(GPUDebugVertex), (float *)vertices.data());
-	}
-
-	if (indices.empty()) {
-		glDrawArrays(glprim[prim], 0, count);
-	} else {
-		glDrawElements(glprim[prim], count, GL_UNSIGNED_SHORT, texPreviewVao != 0 ? 0 : indices.data());
-	}
-
-	if (texPreviewVao == 0) {
-		glDisableVertexAttribArray(previewProgram->a_position);
-	}
-
-	secondWindow->End();
 }
 
 void CGEDebugger::CleanupPrimPreview() {
@@ -337,3 +372,14 @@ void CGEDebugger::CleanupPrimPreview() {
 		glsl_destroy(texPreviewProgram);
 	}
 }
+
+void CGEDebugger::HandleRedraw(int which) {
+	if (updating_) {
+		return;
+	}
+
+	u32 op = PrimPreviewOp();
+	if (op) {
+		UpdatePrimPreview(op, which);
+	}
+}
diff --git a/Windows/ppsspp.rc b/Windows/ppsspp.rc
index 58b2d4ed4b..867613bd9d 100644
--- a/Windows/ppsspp.rc
+++ b/Windows/ppsspp.rc
@@ -657,6 +657,7 @@ BEGIN
     POPUP "gepreviewoptions"
     BEGIN
         MENUITEM "Export Image...",            ID_GEDBG_EXPORT_IMAGE
+        MENUITEM "Show Prim Preview"           ID_GEDBG_ENABLE_PREVIEW
     END
 END
 
diff --git a/Windows/resource.h b/Windows/resource.h
index 32710e3859..ba90e1ac79 100644
--- a/Windows/resource.h
+++ b/Windows/resource.h
@@ -335,6 +335,7 @@
 #define ID_HELP_GITHUB                   40168
 #define IDC_GEDBG_RECORD                 40169
 #define ID_GEDBG_EXPORT_IMAGE            40170
+#define ID_GEDBG_ENABLE_PREVIEW          40171
 
 // Dummy option to let the buffered rendering hotkey cycle through all the options.
 #define ID_OPTIONS_BUFFEREDRENDERINGDUMMY 40500
@@ -347,7 +348,7 @@
 #ifdef APSTUDIO_INVOKED
 #ifndef APSTUDIO_READONLY_SYMBOLS
 #define _APS_NEXT_RESOURCE_VALUE        256
-#define _APS_NEXT_COMMAND_VALUE         40171
+#define _APS_NEXT_COMMAND_VALUE         40172
 #define _APS_NEXT_CONTROL_VALUE         1200
 #define _APS_NEXT_SYMED_VALUE           101
 #endif