Panda3DS/src/core/renderer_gl/renderer_gl.cpp
fleroviux 4322ebda2c [GPU] Start texture combiner implementation
This commit first implements experimental and incomplete
texture combiner support. Currently only the first texture combiner
is implemented. Many sources and combine modes are not implemented yet.
2023-06-15 22:45:13 +02:00

603 lines
No EOL
21 KiB
C++

#include "renderer_gl/renderer_gl.hpp"
#include "PICA/float_types.hpp"
#include "PICA/gpu.hpp"
#include "PICA/regs.hpp"
using namespace Floats;
using namespace Helpers;
// This is all hacked up to display our first triangle
const char* vertexShader = R"(
#version 410 core
layout (location = 0) in vec4 coords;
layout (location = 1) in vec4 vertexColour;
layout (location = 2) in vec2 inUVs_texture0;
out vec4 colour;
out vec2 tex0_UVs;
void main() {
gl_Position = coords;
colour = vertexColour;
// Flip y axis of UVs because OpenGL uses an inverted y for texture sampling compared to the PICA
tex0_UVs = vec2(inUVs_texture0.x, 1.0 - inUVs_texture0.y);
}
)";
const char* fragmentShader = R"(
#version 410 core
in vec4 colour;
in vec2 tex0_UVs;
out vec4 fragColour;
uniform uint u_alphaControl;
uniform uint u_textureConfig;
// TEV uniforms
// TODO: use arrays to handle TEVs 1-3.
uniform uint u_textureEnv0Source;
uniform uint u_textureEnv0Operand;
uniform uint u_textureEnv0Combiner;
uniform vec4 u_textureEnv0Color; // TODO: -> Colour
uniform uint u_textureEnv0Scale;
// Depth control uniforms
uniform float u_depthScale;
uniform float u_depthOffset;
uniform bool u_depthmapEnable;
uniform sampler2D u_tex0;
vec4 tev_evaluate_source(int src_id) {
vec4 source = vec4(1.0);
uint rgb_source = (u_textureEnv0Source >> (src_id * 4)) & 15u;
uint alpha_source = (u_textureEnv0Source >> (16 + src_id * 4)) & 15u;
// TODO: get rid of redundant texture fetches during TEV evaluation.
switch (rgb_source) {
case 0u: source.rgb = colour.rgb; break; // Primary color, TODO: confirm that this is correct
case 3u: source.rgb = texture(u_tex0, tex0_UVs).rgb; break; // Texture 0
case 14u: source.rgb = u_textureEnv0Color.rgb; break; // Constant (GPUREG_TEXENVi_COLOR)
default: break; // TODO: implement remaining sources
}
switch (alpha_source) {
case 0u: source.a = colour.a; break; // Primary color, TODO: confirm that this is correct
case 3u: source.a = texture(u_tex0, tex0_UVs).a; break; // Texture 0
case 14u: source.a = u_textureEnv0Color.a; break; // Constant (GPUREG_TEXENVi_COLOR)
default: break; // TODO: implement remaining sources
}
uint rgb_operand = (u_textureEnv0Operand >> (src_id * 4)) & 15u;
uint alpha_operand = (u_textureEnv0Operand >> (12 + src_id * 4)) & 7u;
vec4 final;
switch (rgb_operand) {
case 0u: final.rgb = source.rgb; break; // Source color
case 1u: final.rgb = 1.0 - source.rgb; break; // One minus source color
case 2u: final.rgb = vec3(source.a); break; // Source alpha
case 3u: final.rgb = vec3(1.0 - source.a); break; // One minus source alpha
case 4u: final.rgb = vec3(source.r); break; // Source red
case 5u: final.rgb = vec3(1.0 - source.r); break; // One minus source red
case 8u: final.rgb = vec3(source.g); break; // Source green
case 9u: final.rgb = vec3(1.0 - source.g); break; // One minus source green
case 12u: final.rgb = vec3(source.b); break; // Source blue
case 13u: final.rgb = vec3(1.0 - source.b); break; // One minus source blue
default: break; // TODO: figure out what the undocumented values do
}
switch (alpha_operand) {
case 0u: final.a = source.a; break; // Source alpha
case 1u: final.a = 1.0 - source.a; break; // One minus source alpha
case 2u: final.a = source.r; break; // Source red
case 3u: final.a = 1.0 - source.r; break; // One minus source red
case 4u: final.a = source.g; break; // Source green
case 5u: final.a = 1.0 - source.g; break; // One minus source green
case 6u: final.a = source.b; break; // Source blue
case 7u: final.a = 1.0 - source.b; break; // One minus source blue
}
// TODO: respect GPUREG_TEXENVi_SCALE
return final;
}
vec4 tev_combine() {
vec4 source0 = tev_evaluate_source(0);
vec4 source1 = tev_evaluate_source(1);
vec4 source2 = tev_evaluate_source(2);
uint rgb_combine = u_textureEnv0Combiner & 15u;
uint alpha_combine = (u_textureEnv0Combiner >> 16) & 15u;
vec4 result = vec4(1.0);
// TODO: figure out how most of the combine modes work.
switch (rgb_combine) {
case 1u: result.rgb = source0.rgb * source1.rgb * source2.rgb; break; // Modulate
default: return vec4(1.0, 0.0, 0.0, 1.0);
}
switch (alpha_combine) {
case 1u: result.a = source0.a * source1.a * source2.a; break; // Modulate
default: return vec4(1.0, 0.0, 0.0, 1.0);
}
return result;
}
void main() {
if ((u_textureConfig & 1u) != 0) { // Render texture 0 if enabled
fragColour = texture(u_tex0, tex0_UVs);
} else {
fragColour = colour;
}
// Get original depth value by converting from [near, far] = [0, 1] to [-1, 1]
// We do this by converting to [0, 2] first and subtracting 1 to go to [-1, 1]
float z_over_w = gl_FragCoord.z * 2.0f - 1.0f;
float depth = z_over_w * u_depthScale + u_depthOffset;
if (!u_depthmapEnable) // Divide z by w if depthmap enable == 0 (ie using W-buffering)
depth /= gl_FragCoord.w;
// Write final fragment depth
gl_FragDepth = depth;
if ((u_alphaControl & 1u) != 0u) { // Check if alpha test is on
uint func = (u_alphaControl >> 4u) & 7u;
float reference = float((u_alphaControl >> 8u) & 0xffu) / 255.0;
float alpha = fragColour.a;
switch (func) {
case 0: discard; // Never pass alpha test
case 1: break; // Always pass alpha test
case 2: // Pass if equal
if (alpha != reference)
discard;
break;
case 3: // Pass if not equal
if (alpha == reference)
discard;
break;
case 4: // Pass if less than
if (alpha >= reference)
discard;
break;
case 5: // Pass if less than or equal
if (alpha > reference)
discard;
break;
case 6: // Pass if greater than
if (alpha <= reference)
discard;
break;
case 7: // Pass if greater than or equal
if (alpha < reference)
discard;
break;
}
}
}
)";
const char* displayVertexShader = R"(
#version 410 core
out vec2 UV;
void main() {
const vec4 positions[4] = vec4[](
vec4(-1.0, 1.0, 1.0, 1.0), // Top-left
vec4(1.0, 1.0, 1.0, 1.0), // Top-right
vec4(-1.0, -1.0, 1.0, 1.0), // Bottom-left
vec4(1.0, -1.0, 1.0, 1.0) // Bottom-right
);
// The 3DS displays both screens' framebuffer rotated 90 deg counter clockwise
// So we adjust our texcoords accordingly
const vec2 texcoords[4] = vec2[](
vec2(1.0, 1.0), // Top-right
vec2(1.0, 0.0), // Bottom-right
vec2(0.0, 1.0), // Top-left
vec2(0.0, 0.0) // Bottom-left
);
gl_Position = positions[gl_VertexID];
UV = texcoords[gl_VertexID];
}
)";
const char* displayFragmentShader = R"(
#version 410 core
in vec2 UV;
out vec4 FragColor;
uniform sampler2D u_texture;
void main() {
FragColor = texture(u_texture, UV);
}
)";
void Renderer::reset() {
depthBufferCache.reset();
colourBufferCache.reset();
textureCache.reset();
// Init the colour/depth buffer settings to some random defaults on reset
colourBufferLoc = 0;
colourBufferFormat = ColourBuffer::Formats::RGBA8;
depthBufferLoc = 0;
depthBufferFormat = DepthBuffer::Formats::Depth16;
if (triangleProgram.exists()) {
const auto oldProgram = OpenGL::getProgram();
triangleProgram.use();
oldAlphaControl = 0; // Default alpha control to 0
oldTexUnitConfig = 0; // Default tex unit config to 0
oldDepthScale = -1.0; // Default depth scale to -1.0, which is what games typically use
oldDepthOffset = 0.0; // Default depth offset to 0
oldDepthmapEnable = false; // Enable w buffering
glUniform1ui(alphaControlLoc, oldAlphaControl);
glUniform1ui(texUnitConfigLoc, oldTexUnitConfig);
glUniform1f(depthScaleLoc, oldDepthScale);
glUniform1f(depthOffsetLoc, oldDepthOffset);
glUniform1i(depthmapEnableLoc, oldDepthmapEnable);
glUseProgram(oldProgram); // Switch to old GL program
}
}
void Renderer::initGraphicsContext() {
OpenGL::Shader vert(vertexShader, OpenGL::Vertex);
OpenGL::Shader frag(fragmentShader, OpenGL::Fragment);
triangleProgram.create({ vert, frag });
triangleProgram.use();
alphaControlLoc = OpenGL::uniformLocation(triangleProgram, "u_alphaControl");
texUnitConfigLoc = OpenGL::uniformLocation(triangleProgram, "u_textureConfig");
textureEnv0SourceLoc = OpenGL::uniformLocation(triangleProgram, "u_textureEnv0Source");
textureEnv0OperandLoc = OpenGL::uniformLocation(triangleProgram, "u_textureEnv0Operand");
textureEnv0CombinerLoc = OpenGL::uniformLocation(triangleProgram, "u_textureEnv0Combiner");
textureEnv0ColorLoc = OpenGL::uniformLocation(triangleProgram, "u_textureEnv0Color");
textureEnv0ScaleLoc = OpenGL::uniformLocation(triangleProgram, "u_textureEnv0Scale");
depthScaleLoc = OpenGL::uniformLocation(triangleProgram, "u_depthScale");
depthOffsetLoc = OpenGL::uniformLocation(triangleProgram, "u_depthOffset");
depthmapEnableLoc = OpenGL::uniformLocation(triangleProgram, "u_depthmapEnable");
glUniform1i(OpenGL::uniformLocation(triangleProgram, "u_tex0"), 0); // Init sampler object
OpenGL::Shader vertDisplay(displayVertexShader, OpenGL::Vertex);
OpenGL::Shader fragDisplay(displayFragmentShader, OpenGL::Fragment);
displayProgram.create({ vertDisplay, fragDisplay });
displayProgram.use();
glUniform1i(OpenGL::uniformLocation(displayProgram, "u_texture"), 0); // Init sampler object
vbo.createFixedSize(sizeof(Vertex) * vertexBufferSize, GL_STREAM_DRAW);
vbo.bind();
vao.create();
vao.bind();
// Position (x, y, z, w) attributes
vao.setAttributeFloat<float>(0, 4, sizeof(Vertex), offsetof(Vertex, position));
vao.enableAttribute(0);
// Colour attribute
vao.setAttributeFloat<float>(1, 4, sizeof(Vertex), offsetof(Vertex, colour));
vao.enableAttribute(1);
// UV attribute
vao.setAttributeFloat<float>(2, 2, sizeof(Vertex), offsetof(Vertex, UVs));
vao.enableAttribute(2);
dummyVBO.create();
dummyVAO.create();
// Create texture and framebuffer for the 3DS screen
const u32 screenTextureWidth = 2 * 400; // Top screen is 400 pixels wide, bottom is 320
const u32 screenTextureHeight = 2 * 240; // Both screens are 240 pixels tall
auto prevTexture = OpenGL::getTex2D();
screenTexture.create(screenTextureWidth, screenTextureHeight, GL_RGBA8);
screenTexture.bind();
screenTexture.setMinFilter(OpenGL::Linear);
screenTexture.setMagFilter(OpenGL::Linear);
glBindTexture(GL_TEXTURE_2D, prevTexture);
screenFramebuffer.createWithDrawTexture(screenTexture);
screenFramebuffer.bind(OpenGL::DrawAndReadFramebuffer);
if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
Helpers::panic("Incomplete framebuffer");
// TODO: This should not clear the framebuffer contents. It should load them from VRAM.
GLint oldViewport[4];
glGetIntegerv(GL_VIEWPORT, oldViewport);
OpenGL::setViewport(screenTextureWidth, screenTextureHeight);
OpenGL::setClearColor(0.0, 0.0, 0.0, 1.0);
OpenGL::clearColor();
OpenGL::setViewport(oldViewport[0], oldViewport[1], oldViewport[2], oldViewport[3]);
reset();
}
// Set up the OpenGL blending context to match the emulated PICA
void Renderer::setupBlending() {
const bool blendingEnabled = (regs[PICAInternalRegs::ColourOperation] & (1 << 8)) != 0;
// Map of PICA blending equations to OpenGL blending equations. The unused blending equations are equivalent to equation 0 (add)
static constexpr std::array<GLenum, 8> blendingEquations = {
GL_FUNC_ADD, GL_FUNC_SUBTRACT, GL_FUNC_REVERSE_SUBTRACT, GL_MIN, GL_MAX, GL_FUNC_ADD, GL_FUNC_ADD, GL_FUNC_ADD
};
// Map of PICA blending funcs to OpenGL blending funcs. Func = 15 is undocumented and stubbed to GL_ONE for now
static constexpr std::array<GLenum, 16> blendingFuncs = {
GL_ZERO, GL_ONE, GL_SRC_COLOR, GL_ONE_MINUS_SRC_COLOR, GL_DST_COLOR, GL_ONE_MINUS_DST_COLOR, GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA,
GL_DST_ALPHA, GL_ONE_MINUS_DST_ALPHA, GL_CONSTANT_COLOR, GL_ONE_MINUS_CONSTANT_COLOR, GL_CONSTANT_ALPHA, GL_ONE_MINUS_CONSTANT_ALPHA,
GL_SRC_ALPHA_SATURATE, GL_ONE
};
if (!blendingEnabled) {
OpenGL::disableBlend();
} else {
OpenGL::enableBlend();
// Get blending equations
const u32 blendControl = regs[PICAInternalRegs::BlendFunc];
const u32 rgbEquation = blendControl & 0x7;
const u32 alphaEquation = getBits<8, 3>(blendControl);
// Get blending functions
const u32 rgbSourceFunc = getBits<16, 4>(blendControl);
const u32 rgbDestFunc = getBits<20, 4>(blendControl);
const u32 alphaSourceFunc = getBits<24, 4>(blendControl);
const u32 alphaDestFunc = getBits<28, 4>(blendControl);
const u32 constantColor = regs[PICAInternalRegs::BlendColour];
const u32 r = constantColor & 0xff;
const u32 g = getBits<8, 8>(constantColor);
const u32 b = getBits<16, 8>(constantColor);
const u32 a = getBits<24, 8>(constantColor);
OpenGL::setBlendColor(float(r) / 255.f, float(g) / 255.f, float(b) / 255.f, float(a) / 255.f);
// Translate equations and funcs to their GL equivalents and set them
glBlendEquationSeparate(blendingEquations[rgbEquation], blendingEquations[alphaEquation]);
glBlendFuncSeparate(blendingFuncs[rgbSourceFunc], blendingFuncs[rgbDestFunc], blendingFuncs[alphaSourceFunc], blendingFuncs[alphaDestFunc]);
}
}
void Renderer::drawVertices(OpenGL::Primitives primType, Vertex* vertices, u32 count) {
OpenGL::disableScissor();
vbo.bind();
vao.bind();
triangleProgram.use();
// Adjust alpha test if necessary
const u32 alphaControl = regs[PICAInternalRegs::AlphaTestConfig];
if (alphaControl != oldAlphaControl) {
oldAlphaControl = alphaControl;
glUniform1ui(alphaControlLoc, alphaControl);
}
setupBlending();
OpenGL::Framebuffer poop = getColourFBO();
poop.bind(OpenGL::DrawAndReadFramebuffer);
const u32 depthControl = regs[PICAInternalRegs::DepthAndColorMask];
const bool depthEnable = depthControl & 1;
const bool depthWriteEnable = getBit<12>(depthControl);
const int depthFunc = getBits<4, 3>(depthControl);
const int colourMask = getBits<8, 4>(depthControl);
glColorMask(colourMask & 1, colourMask & 2, colourMask & 4, colourMask & 8);
static constexpr std::array<GLenum, 8> depthModes = {
GL_NEVER, GL_ALWAYS, GL_EQUAL, GL_NOTEQUAL, GL_LESS, GL_LEQUAL, GL_GREATER, GL_GEQUAL
};
const float depthScale = f24::fromRaw(regs[PICAInternalRegs::DepthScale] & 0xffffff).toFloat32();
const float depthOffset = f24::fromRaw(regs[PICAInternalRegs::DepthOffset] & 0xffffff).toFloat32();
const bool depthMapEnable = regs[PICAInternalRegs::DepthmapEnable] & 1;
// Update depth uniforms
if (oldDepthScale != depthScale) {
oldDepthScale = depthScale;
glUniform1f(depthScaleLoc, depthScale);
}
if (oldDepthOffset != depthOffset) {
oldDepthOffset = depthOffset;
glUniform1f(depthOffsetLoc, depthOffset);
}
if (oldDepthmapEnable != depthMapEnable) {
oldDepthmapEnable = depthMapEnable;
glUniform1i(depthmapEnableLoc, depthMapEnable);
}
// TODO: only update TEV uniforms when the configuration changes.
// TODO: define registers in the PICAInternalRegs enumeration
glUniform1ui(textureEnv0SourceLoc, regs[0xc0]);
glUniform1ui(textureEnv0OperandLoc, regs[0xc1]);
glUniform1ui(textureEnv0CombinerLoc, regs[0xc2]);
{
const u32 rgba = regs[0xc3];
const float r = (float)(rgba & 0xff) / 255.0f;
const float g = (float)((rgba >> 8) & 0xff) / 255.0f;
const float b = (float)((rgba >> 16) & 0xff) / 255.0f;
const float a = (float)(rgba >> 24) / 255.0f;
glUniform4f(textureEnv0ColorLoc, r, g, b, a);
}
glUniform1ui(textureEnv0ScaleLoc, regs[0xc4]);
// Hack for rendering texture 1
if (regs[0x80] & 1) {
const u32 dim = regs[0x82];
const u32 config = regs[0x83];
const u32 height = dim & 0x7ff;
const u32 width = getBits<16, 11>(dim);
const u32 addr = (regs[0x85] & 0x0FFFFFFF) << 3;
const u32 format = regs[0x8E] & 0xF;
Texture targetTex(addr, static_cast<Texture::Formats>(format), width, height, config);
OpenGL::Texture tex = getTexture(targetTex);
tex.bind();
}
// Update the texture unit configuration uniform if it changed
const u32 texUnitConfig = regs[PICAInternalRegs::TexUnitCfg];
if (oldTexUnitConfig != texUnitConfig) {
oldTexUnitConfig = texUnitConfig;
glUniform1ui(texUnitConfigLoc, texUnitConfig);
}
// TODO: Actually use this
float viewportWidth = f24::fromRaw(regs[PICAInternalRegs::ViewportWidth] & 0xffffff).toFloat32() * 2.0;
float viewportHeight = f24::fromRaw(regs[PICAInternalRegs::ViewportHeight] & 0xffffff).toFloat32() * 2.0;
OpenGL::setViewport(viewportWidth, viewportHeight);
// Note: The code below must execute after we've bound the colour buffer & its framebuffer
// Because it attaches a depth texture to the aforementioned colour buffer
if (depthEnable) {
OpenGL::enableDepth();
glDepthFunc(depthModes[depthFunc]);
glDepthMask(depthWriteEnable ? GL_TRUE : GL_FALSE);
bindDepthBuffer();
} else {
if (depthWriteEnable) {
OpenGL::enableDepth();
glDepthFunc(GL_ALWAYS);
glDepthMask(GL_TRUE);
bindDepthBuffer();
} else {
OpenGL::disableDepth();
}
}
vbo.bufferVertsSub(vertices, count);
OpenGL::draw(primType, count);
}
constexpr u32 topScreenBuffer = 0x1f000000;
constexpr u32 bottomScreenBuffer = 0x1f05dc00;
// Quick hack to display top screen for now
void Renderer::display() {
OpenGL::disableScissor();
glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
screenFramebuffer.bind(OpenGL::ReadFramebuffer);
glBlitFramebuffer(0, 0, 400, 480, 0, 0, 400, 480, GL_COLOR_BUFFER_BIT, GL_LINEAR);
}
void Renderer::clearBuffer(u32 startAddress, u32 endAddress, u32 value, u32 control) {
return;
log("GPU: Clear buffer\nStart: %08X End: %08X\nValue: %08X Control: %08X\n", startAddress, endAddress, value, control);
const float r = float(getBits<24, 8>(value)) / 255.0;
const float g = float(getBits<16, 8>(value)) / 255.0;
const float b = float(getBits<8, 8>(value)) / 255.0;
const float a = float(value & 0xff) / 255.0;
if (startAddress == topScreenBuffer) {
log("GPU: Cleared top screen\n");
} else if (startAddress == bottomScreenBuffer) {
log("GPU: Tried to clear bottom screen\n");
return;
} else {
log("GPU: Clearing some unknown buffer\n");
}
OpenGL::setClearColor(r, g, b, a);
OpenGL::clearColor();
}
OpenGL::Framebuffer Renderer::getColourFBO() {
//We construct a colour buffer object and see if our cache has any matching colour buffers in it
// If not, we allocate a texture & FBO for our framebuffer and store it in the cache
ColourBuffer sampleBuffer(colourBufferLoc, colourBufferFormat, fbSize.x(), fbSize.y());
auto buffer = colourBufferCache.find(sampleBuffer);
if (buffer.has_value()) {
return buffer.value().get().fbo;
} else {
return colourBufferCache.add(sampleBuffer).fbo;
}
}
void Renderer::bindDepthBuffer() {
// Similar logic as the getColourFBO function
DepthBuffer sampleBuffer(depthBufferLoc, depthBufferFormat, fbSize.x(), fbSize.y());
auto buffer = depthBufferCache.find(sampleBuffer);
GLuint tex;
if (buffer.has_value()) {
tex = buffer.value().get().texture.m_handle;
} else {
tex = depthBufferCache.add(sampleBuffer).texture.m_handle;
}
if (DepthBuffer::Formats::Depth24Stencil8 != depthBufferFormat) Helpers::panic("TODO: Should we remove stencil attachment?");
auto attachment = depthBufferFormat == DepthBuffer::Formats::Depth24Stencil8 ? GL_DEPTH_STENCIL_ATTACHMENT : GL_DEPTH_ATTACHMENT;
glFramebufferTexture2D(GL_FRAMEBUFFER, attachment, GL_TEXTURE_2D, tex, 0);
}
OpenGL::Texture Renderer::getTexture(Texture& tex) {
// Similar logic as the getColourFBO/bindDepthBuffer functions
auto buffer = textureCache.find(tex);
if (buffer.has_value()) {
return buffer.value().get().texture;
} else {
const void* textureData = gpu.getPointerPhys<void*>(tex.location); // Get pointer to the texture data in 3DS memory
Texture& newTex = textureCache.add(tex);
newTex.decodeTexture(textureData);
return newTex.texture;
}
}
void Renderer::displayTransfer(u32 inputAddr, u32 outputAddr, u32 inputSize, u32 outputSize, u32 flags) {
const u32 inputWidth = inputSize & 0xffff;
const u32 inputGap = inputSize >> 16;
const u32 outputWidth = outputSize & 0xffff;
const u32 outputGap = outputSize >> 16;
auto framebuffer = colourBufferCache.findFromAddress(inputAddr);
// If there's a framebuffer at this address, use it. Otherwise go back to our old hack and display framebuffer 0
// Displays are hard I really don't want to try implementing them because getting a fast solution is terrible
OpenGL::Texture& tex = framebuffer.has_value() ? framebuffer.value().get().texture : colourBufferCache[0].texture;
tex.bind();
screenFramebuffer.bind(OpenGL::DrawFramebuffer);
OpenGL::disableBlend();
OpenGL::disableDepth();
OpenGL::disableScissor();
displayProgram.use();
// Hack: Detect whether we are writing to the top or bottom screen by checking output gap and drawing to the proper part of the output texture
// We consider output gap == 320 to mean bottom, and anything else to mean top
if (outputGap == 320) {
OpenGL::setViewport(40, 0, 320, 240); // Bottom screen viewport
} else {
OpenGL::setViewport(0, 240, 400, 240); // Top screen viewport
}
dummyVAO.bind();
OpenGL::draw(OpenGL::TriangleStrip, 4); // Actually draw our 3DS screen
}