JackCarterSmith
098345409f
Culling isn't bad, clipping need a better approach to cut partial triangles.
211 lines
8.6 KiB
C++
211 lines
8.6 KiB
C++
#include "3DRenderer.hpp"
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#include "../World/DbgCube.hpp"
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#include "../World/Tank.hpp"
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//#define DISABLE_INVISIBLE_VERTICES
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// Rendering pipeline:
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// model matrix (Object SRT) -> view matrix (camera matrix inverted) -> proj matrix -> clipping -> perspective divide -> viewport transformation -> Rasterizer (draw pixels inside projected triangles on 2D screen)
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// object space -> world space -> camera space -> homogeneous clip space -> NDC space -> raster space
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//
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// Rasterizer inputs elements:
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// - texture-buffer (2D array of pixels color value)
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// - z-buffer (2D array of float representing the nearest pixel's depth, all pixels beyond are ignored)
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// - projected vertices-buffer on screen (using vertices-buffer and projection function)
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//
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// Refs:
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// * https://en.wikipedia.org/wiki/3D_projection
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// * https://www.scratchapixel.com/lessons/3d-basic-rendering/rasterization-practical-implementation/overview-rasterization-algorithm.html
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// * https://ktstephano.github.io/rendering/stratusgfx/aabbs
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// * https://en.wikipedia.org/wiki/Clipping_(computer_graphics)
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// * https://www.coranac.com/tonc/text/mode7.htm
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// * https://en.wikipedia.org/wiki/Back-face_culling
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// * https://en.wikipedia.org/wiki/Hidden-surface_determination#Occlusion_culling
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// * https://en.wikipedia.org/wiki/Bounding_volume_hierarchy
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static bool VertexIsInsideClipSpace(M3D_F4& V);
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Graphic3DRenderer::Graphic3DRenderer() {
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mRTSize = {1280.f, 324.f};
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if (mMainCamera == nullptr) {
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mMainCamera = std::make_unique<Camera>();
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mMainCamera->SetPosition(0.0f, 1.5f, -8.0f);
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mMainCamera->SetFrustrum(90.0f, mRTSize.x/mRTSize.y, 1.0f, 100.f);
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mMainCamera->UpdateCamView();
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}
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// Fill world object list to render
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mRenderList.clear();
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mRenderList.push_back(std::make_shared<ObjectDbgCube>());
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mRenderList.back()->SetPosition(0.f, 0.f, 15.f);
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mRenderList.back()->SetScale(2.0f);
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mRenderList.push_back(std::make_shared<ObjectDbgCube>());
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mRenderList.back()->SetPosition(6.f, 2.f, 2.f);
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mRenderList.back()->SetScale(2.0f);
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mRenderList.push_back(std::make_shared<ObjectDbgCube>());
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mRenderList.back()->SetPosition(-8.f, 5.f, 10.f);
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mRenderList.back()->SetScale(2.0f);
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mRenderList.push_back(std::make_shared<Tank>());
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mRenderList.back()->SetPosition(0.f, 0.f, 0.f);
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mRenderList.back()->SetScale(5.0f);
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}
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Graphic3DRenderer::~Graphic3DRenderer() {}
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void Graphic3DRenderer::SetRTSize(unsigned int w, unsigned int h) {
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mRTSize.x = w; mRTSize.y = h;
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mMainCamera->SetFrustrum(90.0f, mRTSize.x/mRTSize.y, 1.0f, 100.f);
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}
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void Graphic3DRenderer::UpdateCamera(CAMERA_MOVE type, const float value) {
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switch (type) {
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case CAMERA_MOVE_WALK:
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mMainCamera->Walk(value);
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break;
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case CAMERA_MOVE_STRAFE:
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mMainCamera->Strafe(value);
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break;
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case CAMERA_MOVE_FLY:
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mMainCamera->Fly(value);
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break;
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case CAMERA_MOVE_PITCH:
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mMainCamera->Pitch(value);
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break;
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case CAMERA_MOVE_YAW:
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mMainCamera->Yaw(value);
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break;
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default:
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break;
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}
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mMainCamera->UpdateCamView();
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}
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void Graphic3DRenderer::Draw(sf::RenderTexture& context) {
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sf::BlendMode sBM = sf::BlendNone;
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sf::RenderStates sRS(sBM);
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// Hardcoded debug movement, TODO: remove it
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UpdateInternalTestObjects();
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// Load main matrices
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M3D_MATRIX viewMat = mMainCamera->GetView();
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M3D_MATRIX projMat = mMainCamera->GetProj();
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M3D_MATRIX viewProjMat = viewMat * projMat;
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// Create the frustrum "box"
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M3D_BoundingFrustum camFrustrum(projMat, false);
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camFrustrum.Transform(camFrustrum, M3D_MInverse(viewMat));
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// Process scene's objects
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for (auto& obj : mRenderList) {
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M3D_BoundingBox projAABB = obj->GetAABB();
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auto oTMat = obj->GetTransform();
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// Object outside frustrum clipping
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projAABB.Transform(projAABB, oTMat);
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M3D_ContainmentType objInFrustrum = camFrustrum.Contains(projAABB);
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#ifndef DISABLE_INVISIBLE_VERTICES
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if (objInFrustrum != DISJOINT)
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#endif
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{
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size_t vCount = obj->GetObjectVerticesCount();
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auto& oMesh = obj->GetObjectMesh();
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M3D_F4 projVertices[vCount];
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// Vertices homogeneous clip space transformation
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M3D_V3Transform(
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projVertices, sizeof(M3D_F4),
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reinterpret_cast<const M3D_F3*>(oMesh.vertices.data()), sizeof(Vertex),
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vCount,
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oTMat * viewProjMat
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);
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// Draw the object indice triangles if visible or partially clipped
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sf::Vertex v_tri[4];
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for (auto& objPt : oMesh.parts) {
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auto indicePtr = static_cast<const uint32_t*>(objPt.indices.data());
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for (uint32_t i = 0; i < objPt.GetIndicesCount(); i += 3) {
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// Misscontructed indices tree failsafe
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if (i+2 > objPt.GetIndicesCount())
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break;
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// Triangle clipping
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//TODO: implement complete Cohen-Sutherland algo or similar
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if (VertexIsInsideClipSpace(projVertices[indicePtr[i]]) &&
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VertexIsInsideClipSpace(projVertices[indicePtr[i+1]]) &&
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VertexIsInsideClipSpace(projVertices[indicePtr[i+2]]))
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{
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M3D_VECTOR V1 = M3D_V4LoadF4(&projVertices[indicePtr[i]]);
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M3D_VECTOR V2 = M3D_V4LoadF4(&projVertices[indicePtr[i+1]]);
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M3D_VECTOR V3 = M3D_V4LoadF4(&projVertices[indicePtr[i+2]]);
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// Face culling
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M3D_VECTOR faceNormal = M3D_TNormal(V1,V2,V3);
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if (M3D_V4GetX(M3D_V3Dot(V1, faceNormal)) >= 0) {
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// Do the perspective divide
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V1 = M3D_V4Divide(V1, M3D_V4SplatW(V1));
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V2 = M3D_V4Divide(V2, M3D_V4SplatW(V2));
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V3 = M3D_V4Divide(V3, M3D_V4SplatW(V3));
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V1 = M3D_V3TransformNDCToViewport(V1, 0.f, 0.f, mRTSize.x, mRTSize.y, 1.f, 100.f);
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V2 = M3D_V3TransformNDCToViewport(V2, 0.f, 0.f, mRTSize.x, mRTSize.y, 1.f, 100.f);
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V3 = M3D_V3TransformNDCToViewport(V3, 0.f, 0.f, mRTSize.x, mRTSize.y, 1.f, 100.f);
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if (objInFrustrum == DISJOINT) {
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v_tri[0].color = sf::Color::Red;
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v_tri[1].color = sf::Color::Red;
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v_tri[2].color = sf::Color::Red;
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} else if (objInFrustrum == INTERSECTS) {
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v_tri[0].color = sf::Color::Yellow;
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v_tri[1].color = sf::Color::Yellow;
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v_tri[2].color = sf::Color::Yellow;
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} else {
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v_tri[0].color = oMesh.vertices[indicePtr[i]].color;
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v_tri[1].color = oMesh.vertices[indicePtr[i+1]].color;
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v_tri[2].color = oMesh.vertices[indicePtr[i+2]].color;
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}
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v_tri[0].position = sf::Vector2f(M3D_V4GetX(V1), M3D_V4GetY(V1));
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v_tri[1].position = sf::Vector2f(M3D_V4GetX(V2), M3D_V4GetY(V2));
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v_tri[2].position = sf::Vector2f(M3D_V4GetX(V3), M3D_V4GetY(V3));
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v_tri[3] = v_tri[0];
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context.draw(v_tri, 4, sf::LineStrip, sRS);
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//context.draw(v_tri, 3, sf::Triangles, sRS);
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}
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}
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}
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}
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}
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}
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}
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void Graphic3DRenderer::UpdateInternalTestObjects() {
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static float thetaAngle = 0.31f;
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thetaAngle = thetaAngle >= 6.283185f ? -6.283185f : thetaAngle + 0.004f;
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static float thetaAngle2 = 2.12f;
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thetaAngle2 = thetaAngle2 >= 6.283185f ? -6.283185f : thetaAngle2 + 0.005f;
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static float thetaAngle3 = -4.78f;
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thetaAngle3 = thetaAngle3 >= 6.283185f ? -6.283185f : thetaAngle3 + 0.008f;
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mRenderList[0]->SetRotation(thetaAngle, 0.f, thetaAngle * 0.5f);
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mRenderList[1]->SetRotation(thetaAngle2, 0.f, thetaAngle2 * 0.5f);
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mRenderList[2]->SetRotation(thetaAngle3, 0.f, thetaAngle3 * 0.5f);
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mRenderList[3]->SetRotation(0.f, thetaAngle, 0.f);
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}
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inline static bool VertexIsInsideClipSpace(M3D_F4& V) {
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return (V.x > -V.w && V.x < V.w &&
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V.y > -V.w && V.y < V.w &&
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V.z > 0 && V.z < V.w
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);
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} |