CSCI E-74. Simulation and Gaming

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1 CSCI E-74 Virtual and Augmented Reality for Simulation and Gaming Fall term 2017 Gianluca De Novi, PhD Lesson 6 Basic Texturing

2 Data Structures in a 3D Engine Vertices/Vectors Segments Matrices Polygons Surfaces Materials Objects (Generic) Super categories of Objects Lights Camera Motion Data Lattices Skeletons Textures Particles CSCI E-74 Virtual and Augmented Reality for Simulation and Gaming 2

3 Data Structure TEngineVR TScene TObject TSurface TPolygon TVertex TObject TSurface TPolygon TVertex TObject TSurface TPolygon TVertex TMaterial TTexture TMaterial TTexture TMaterial TTexture Cameras Motion Data Lights CSCI E-74 Virtual and Augmented Reality for Simulation and Gaming 3

Data Hierarchy TObject TextureList TextureListLen TSurface

Ambient Emissive Shininess Smoothing Doublesided Wireframe

TTexture Image Data [r,g,b,a] ID Name Width Height

4 Data Hierarchy TObject TextureList TextureListLen TSurface VertexList NormalList TexCoords TMaterial Specular Diffuse Ambient Emissive Shininess Smoothing Doublesided Wireframe Visible TextureIDList TextureOperation TextureIDListLen TTexture Image Data [r,g,b,a] ID Name Width Height Interpolation CromaKey KeyColor CSCI E-74 Virtual and Augmented Reality for Simulation and Gaming 4

Texture Loading Workflow Load Image File

Allocation and transfer CSCI E-74 Virtual

5 Texture Loading Workflow Load Image File to RAM Image Pre-Processing Data Transfer Properties Texture ID Generation and Selection Interpolation Settings Video RAM Allocation and transfer CSCI E-74 Virtual and Augmented Reality for Simulation and Gaming 5

6 Texture Drawing Workflow V1(x,y,z) T1(u,v) 0,0 1,0 u V0(x,y,z) T0(u,v) v 0,1 1,1 V2(x,y,z) T2(u,v) Usually square with side lengths power of 2 ( 2x2, 4x4, 8x8, 16x16, 32x32, 64x64, 128x128, 256x256, 512x512, 1024x1024, etc.) CSCI E-74 Virtual and Augmented Reality for Simulation and Gaming 6

7 Texture Drawing Workflow Texture Selection Operation Selection Vertices Normals Texture Coordinates Grapic Rendering CSCI E-74 Virtual and Augmented Reality for Simulation and Gaming 7

8 Textured Triangle Drawing glenable(gl_texture_2d); glbindtexture(gl_texture_2d,textureid); glbegin(gl_triangles); glnormal3f(n0.x,n0.y,n0.z);gltexcoord2f(u0,v1);glvertex3f(v0.x,v0.y,v0.z); glnormal3f(n1.x,n1.y,n1.z);gltexcoord2f(u1,v1);glvertex3f(v1.x,v1.y,v1.z); glnormal3f(n2.x,n2.y,n2.z);gltexcoord2f(u2,v2);glvertex3f(v2.x,v2.y,v2.z); glend(); V1(x,y,z) T1(u,v) gldisable(gl_texture_2d); V0(x,y,z) T0(u,v) V2(x,y,z) T2(u,v) CSCI E-74 Virtual and Augmented Reality for Simulation and Gaming 8

Textured Interpolation 1 2 3 MIPMAP Sets NEAREST as default for small polygons where no interpolation is necessary.

9 Textured Interpolation MIPMAP Sets NEAREST as default for small polygons where no interpolation is necessary. Then automatically switches to LINEAR when the polygons are bigger than the original texture CSCI E-74 Virtual and Augmented Reality for Simulation and Gaming 9

10 Class TTexture #define MAX_TX_NAME 256 class TTexture char Name; unsigned int Width; unsigned int Height; unsigned int ID; int Interpolation; int CromaKey; TColor KeyColor; TTexture(void); ~Ttexture(void); int LoadBMPTexture(char * filename, int InterpolationMode); int BuildTexture(RGBA8 TxData); ; int TTexture::LoadBMPTexture(char * filename, int InterpolationMode) FILE * fp; if(fp=fopen(filename,"r")) fclose(fp); AUX_RGBImageRec * TextureImage=NULL; RGBA8 * pdata; RGB8 * pdatargb; Interpolation = InterpolationMode; if(textureimage=auxdibimageload(filename)) int imagesize = TextureImage->sizeX * TextureImage->sizeY; pdatargb = (RGB8 *)TextureImage->data; pdata = new TColor[TextureImage->sizeX * TextureImage->sizeY]; unsigned int i; for(i=0;i<imagesize;i++) pdata[i].r=pdatargb[i].r; pdata[i].g=pdatargb[i].g; pdata[i].b=pdatargb[i].b; pdata[i].a=(float)(pdata[i].r+pdata[i].g+pdata[i].b)/3.0f; if( pdata[i] == CromKey)pData[i].Clear(); CromaKey=TRUE; Width = TextureImage->sizeX; Height = TextureImage->sizeY; BuildTexture(pData); if(textureimage) if(textureimage->data) delete TextureImage->data; delete TextureImage; if(pdata) delete pdata; return TRUE; return FALSE; typedef struct char b,g,r; RGB8; typedef struct char b,g,r,a; RGBA8; Channel by channel (r,g,b,a) CSCI E-74 Virtual and Augmented Reality for Simulation and Gaming 10

11 Class TTexture #define MAX_TX_NAME 256 class TTexture char Name; unsigned int Width; unsigned int Height; unsigned int ID; int Interpolation; int CromaKey; TColor KeyColor; TTexture(void); ~Ttexture(void); int LoadBMPTexture(char * filename, int InterpolationMode); int BuildTexture(RGBA8 TxData); ; int TTexture::BuildTexture(RGBA8 * TxData) glpixeltransferf(gl_red_scale,1.0f); glpixeltransferf(gl_green_scale,1.0f); glpixeltransferf(gl_blue_scale,1.0f); gltexparameteri (GL_TEXTURE_2D,GL_TEXTURE_WRAP_S,GL_REPEAT ); gltexparameteri (GL_TEXTURE_2D,GL_TEXTURE_WRAP_T,GL_REPEAT ); glgentextures(1,&id); glbindtexture(gl_texture_2d,id); Scale Color During Transfer to Video Memory Repeat Texture Coordinates switch(interpolation) case TXNEAREST :gltexparameteri(gl_texture_2d,gl_texture_min_filter,gl_nearest); gltexparameteri(gl_texture_2d,gl_texture_mag_filter,gl_nearest); glteximage2d (GL_TEXTURE_2D,0,GL_RGBA,Width,Height,0,GL_RGBA,GL_UNSIGNED_BYTE,pData); break; case TXLINEAR :gltexparameteri(gl_texture_2d,gl_texture_min_filter,gl_linear); gltexparameteri(gl_texture_2d,gl_texture_mag_filter,gl_linear); glteximage2d (GL_TEXTURE_2D,0,GL_RGBA,Width,Height,0,GL_RGBA,GL_UNSIGNED_BYTE,pData); break; case TXMIPMAP :gltexparameteri(gl_texture_2d,gl_texture_min_filter,gl_linear); gltexparameteri(gl_texture_2d,gl_texture_mag_filter,gl_linear_mipmap_nearest); glubuild2dmipmaps(gl_texture_2d,gl_rgba,width,height,gl_rgba,gl_unsigned_byte,pdata); break; typedef struct char b,g,r; RGB8; typedef struct char b,g,r,a; RGBA8; Interpolation Selection CSCI E-74 Virtual and Augmented Reality for Simulation and Gaming 11

12 Object Class class TObject public: TPose Pose; //Object Pose Tvector Scale; //Object Scale TMatrix4x4 TRS; //Model View Matrix TMaterial Mlist[ ]; //List of available materials unsigned int MListLen; //Number of materials available TTexture TextureList[ ]; //list of Textures unsigned int TextureListLen; //Number of Textures TSurface SList[ ]; //Surfaces of the Object unsigned int SListLen; //Number of Surfaces int Visible; //Visibility Flag void CalcNormals(); //calculate Normal void BuildjMatrix(); //Builds the TRS Matrix void Draw(); //draw int AddTexture(char * filename, int Interpolation); void DeleteTexture(unsigned int Index); ; For example NB: This model doesn t consider the vertex optimization CSCI E-74 Virtual and Augmented Reality for Simulation and Gaming 12

13 TMaterials Class typedef struct unsigned int ID; unsigned int Operation; TextureLevel; class TMaterial float Ambient [4]; float Specular[4]; float Diffuse [4]; float Emissive[4]; float Color [4]; float Shinines; short Smoothing; short Visible; short Doublesided; short Wireframe; short Visible; TextureLevel TextureList[ ]; unsigned int TextureListLen[ ]; void LoadDefaultMaterial(); void LoadMaterial(); int AddTextureLevel(unsigned int TexID, unsigned int Operation); void RemoveTextureLevel(unsigned int Level); ; CSCI E-74 Virtual and Augmented Reality for Simulation and Gaming 13

14 Surface Class typedef struct float u,v; TTexCoord; class TSurface public: TVertex VList[ ]; //Vertices on the surface unsigned int VListLen; //Number of Vertices TVector NList[ ]; //Normals on the surface TPolygon Plist[ ]; //Polygons on the surface unsigned int PListLen; //Number of Polygons on the surface TMaterial * Material; //Surface color TTexCoord TexCoordList[ ]; //List of Texture Coordinate per Vertex int Visible; //Visibility Flag ; void CalcNormals(); //calculate Normal void Flip(); //flip the normal orientation void Draw(); //draw //assigns the material for the surface void SetSurfaceMaterial(TMaterial * M); NB: This model doesn t consider the vertex optimization CSCI E-74 Virtual and Augmented Reality for Simulation and Gaming 14

15 Polygon Class class TPolygon public: int v0,v1,v2; //indices to the 3 vertices int Visible; //visibility flag TMaterial* Material; //Material Pointer TVector Normal; //Normal vector TVertex* Vlist; //List of Vertices TVector* Nlist; //List of Normal per Vertex TTexCoord * TList; //List of Texture Coordinates void CalcNormal(); //calculate Normal void Flip(); //flip the normal orientation void Draw(); //draw ; void TPolygon::Draw() int I; if(visible) if(material->smoothing) if(material->texturelistlen) for(i=0;i<texturelistlen;i++) glbegin(gl_triangles); glnormal3f(nlist[v0].x, Nlist[v0].y, Nlist[v0].z); gltexcoord2f(tlist[v0].u, TList[v0].v); glvertex3f(vlist[v0].x, Vlist[v0].y, Vlist[v0].z); glnormal3f(nlist[v1].x, Nlist[v1].y, Nlist[v1].z); gltexcoord2f(tlist[v1].u, TList[v1].v); glvertex3f(vlist[v1].x, Vlist[v1].y, Vlist[v1].z); glnormal3f(nlist[v2].x, Nlist[v2].y, Nlist[v2].z); gltexcoord2f(tlist[v2].u, TList[v2].v); glvertex3f(vlist[v2].x, Vlist[v2].y, Vlist[v2].z); glend(); else... else if(material->texturelistlen) glbegin(gl_triangles); glnormal3f(nlist[v0].x, Nlist[v0].y, Nlist[v0].z); gltexcoord2f(tlist[v0].u, TList[v0].v); glvertex3f(vlist[v0].x, Vlist[v0].y, Vlist[v0].z); gltexcoord2f(tlist[v1].u, TList[v1].v); glvertex3f(vlist[v1].x, Vlist[v1].y, Vlist[v1].z); gltexcoord2f(tlist[v2].u, TList[v2].v); glvertex3f(vlist[v2].x, Vlist[v2].y, Vlist[v2].z); glend(); else... NB: This model doesn t consider the vertex optimization CSCI E-74 Virtual and Augmented Reality for Simulation and Gaming 15

16 Texture Coordinates Assuming that: We know how lo load a texture We know how to draw textured primitives How do we generate texture Coordinates? CSCI E-74 Virtual and Augmented Reality for Simulation and Gaming 16

17 Texture Coordinates Generation CSCI E-74 Virtual and Augmented Reality for Simulation and Gaming 17

v = (y-miny)/meshheight; NB: it depends from where the mapping plan is.

18 Method 1: Planar Mapping u = x minx meshwidth v = y miny meshheight int i for(i=0;i<vertexlistlen;i++) TexCoord[i].u = (x-miny)/meshwidth; TexCoord[i].v = (y-miny)/meshheight; NB: it depends from where the mapping plan is. We assume for simplicity that it is parallel to the plane XY CSCI E-74 Virtual and Augmented Reality for Simulation and Gaming 18

Method 2: Cylindrical Mapping u = x 0 x < 0 acos(z/r 0 ) π 360 acos(z/d) π 1 180 1 180 v = y miny meshheight

(float)acos((float)z/dist)/pi; if(x>=0) return a; return 360-a;.

19 Method 2: Cylindrical Mapping u = x 0 x < 0 acos(z/r 0 ) π 360 acos(z/d) π v = y miny meshheight float CalcPolarCoordinate(float x,float z) float dist = sqrt(x*x+z*z); float a = (float)acos((float)z/dist)/pi; if(x>=0) return a; return 360-a;... int i for(i=0;i<vertexlistlen;i++) TexCoord[i].u = CalcPolarCoordinate(x,z); TexCoord[i].v = (y-miny)/meshheight; CSCI E-74 Virtual and Augmented Reality for Simulation and Gaming 19

Method 3: Spherical Mapping u = x 0 acos(z/r 0 ) π 1 180 x < 0 360 acos(z/r 0) π 1 180 v = y 0 y < 0 acos(z/d) π 1 180 360 acos(z/d) π 1 180 int i

20 Method 3: Spherical Mapping u = x 0 acos(z/r 0 ) π x < acos(z/r 0) π v = y 0 y < 0 acos(z/d) π acos(z/d) π int i for(i=0;i<vertexlistlen;i++) TexCoord[i].u = CalcPolarCoordinate(x,z); TexCoord[i].v = CalcPolarCoordinate(y,z); CSCI E-74 Virtual and Augmented Reality for Simulation and Gaming 20

Method 4: Reflection Spherical Map glenable(gl_texture_2d); glbindtexture(gl_texture_2d,texture); gltexgeni(gl_s, GL_TEXTURE_GEN_MODE, GL_SPHERE_MAP); gltexgeni(gl_t, GL_TEXTURE_GEN_MODE,

21 Method 4: Reflection Spherical Map glenable(gl_texture_2d); glbindtexture(gl_texture_2d,texture); gltexgeni(gl_s, GL_TEXTURE_GEN_MODE, GL_SPHERE_MAP); gltexgeni(gl_t, GL_TEXTURE_GEN_MODE, GL_SPHERE_MAP); glenable(gl_texture_gen_t); glenable(gl_texture_gen_s); glbegin(gl_triangle_strip); glnormal3f(n1.x,n1.y,n1.z); glvertex3f(pv1.x,pv1.y,pv1.z); glnormal3f(n2.x,n2.y,n2.z); glvertex3f(pv2.x,pv2.y,pv2.z); glnormal3f(n3.x,n3.y,n3.z); glvertex3f(pv3.x,pv3.y,pv3.z); glend(); gldisable(gl_texture_gen_s); gldisable(gl_texture_gen_t); gldisable(gl_texture_2d); n Ambient R No Texture Coordinates!!! Coordinates are generated in real-time by OpenGL using the normal and its reflection vectors I CSCI E-74 Virtual and Augmented Reality for Simulation and Gaming 21

22 Method 1,2,3: Automatic UV Map CSCI E-74 Virtual and Augmented Reality for Simulation and Gaming 22

23 Method Optimized UV Mapping CSCI E-74 Virtual and Augmented Reality for Simulation and Gaming 23

24 Loading a 3DS (3D Studio file) 0x4D4D // Main Chunk 0x0002 // M3D Version 0x3D3D // 3D Editor Chunk 0x4000 // Object Block 0x4100 // Triangular Mesh 0x4110 // Vertices List 0x4120 // Faces Description 0x4130 // Faces Material 0x4150 // Smoothing Group List 0x4140 // Mapping Coordinates List 0x4160 // Local Coordinates System 0x4600 // Light 0x4610 // Spotlight 0x4700 // Camera 0xAFFF // Material Block 0xA000 // Material Name 0xA010 // Ambient Color 0xA020 // Diffuse Color 0xA030 // Specular Color 0xA200 // Texture Map 1 0xA230 // Bump Map 0xA220 // Reflection Map /* Sub Chunks For Each Map */ 0xA300 // Mapping Filename 0xA351 // Mapping Parameters 0xB000 // Keyframer Chunk 0xB002 // Mesh Information Block 0xB007 // Spot Light Information Block 0xB008 // Frames (Start and End) 0xB010 // Object Name 0xB013 // Object Pivot Point 0xB020 // Position Track 0xB021 // Rotation Track 0xB022 // Scale Track 0xB030 // Hierarchy Position int TObject::Load3DSObject (char * filename) unsigned short l_chunk_id; unsigned int l_chunk_length; unsigned char l_char; unsigned short l_qty; unsigned short l_face_flags; FILE * fp = fopen(filename,"rb"); if(fp) while (ftell (fp) < filelength (fileno (fp))) //Loop to scan the whole file fread (&l_chunk_id, 2, 1, fp); //Read the chunk header fread (&l_chunk_length, 4, 1, fp); //Read the length of the chunk switch (l_chunk_id) case 0x4d4d:... break; case 0x3d3d:... break; case 0x4000:... break;... case 0xB030:... break; CSCI E-74 Virtual and Augmented Reality for Simulation and Gaming 24

25 What can I do with Texture Mapping? CSCI E-74 Virtual and Augmented Reality for Simulation and Gaming 25

26 Multitexturing CSCI E-74 Virtual and Augmented Reality for Simulation and Gaming 26

CSCI E-74. Simulation and Gaming

CSCI E-74. Simulation and Gaming CSCI E-74 Virtual and Augmented Reality for Simulation and Gaming Fall term 2017 Gianluca De Novi, PhD Lesson 5 Basic Lighting and Materials Data Structures in a 3D Engine Vertices/Vectors Segments Matrices