'' '' Project: FreeBASIC OpenGL examples '' File: lesson08.bas '' '' Purpose: '' Demonstrate texture filtering, lighting, and blending on a rotating '' textured cube. '' '' Ownership: '' LoadGLTextures owns its temporary decoded bitmap and transfers pixels '' into three module-owned OpenGL texture names. The render loop releases '' those names when it ends. '' '' This file intentionally does NOT contain: '' - a general texture asset manager '' - graphics state outside the single render loop '' '' This Code Was Created By Jeff Molofee 2000 '' A HUGE Thanks To Fredric Echols For Cleaning Up '' And Optimizing The Base Code, Making It More Flexible! '' If You've Found This Code Useful, Please Let Me Know. '' Visit My Site At nehe.gamedev.net '' '' compile as: fbc -s gui lesson08.bas ''------------------------------------------------------------------------------ '' Use ESC key to quit '' L key to toggle lighting (on/off) '' F key to cycle filters (Nearest, Linear , MipMapped) '' B key to toggle blending (on/off) '' PgUp key and PgDn key to Zoom in and out '' UpArrow, DnArrow, RightArrow, Left Arrow to change rotate speed of cube '' ''------------------------------------------------------------------------------ #include once "GL/gl.bi" #include once "GL/glu.bi" #include once "bmpload.bi" #include once "fbgfx.bi" ''for Scan code constants '' Setup our booleans declare function LoadGLTextures() as integer '' LoadGLTextures and the one render loop share these module-local controls. '' FB-LINTER: DISABLE-NEXT-LINE FBL301 dim shared filter as uinteger '' Which Filter To Use dim shared texture(0 to 2) as GLuint '' Storage For 3 Textures dim shared light as integer '' Lighting ON/OFF dim shared blend as integer '' Blending OFF/ON? ( NEW ) dim shared lp as integer '' L Pressed? dim shared fp as integer '' F Pressed? dim shared blendpressed as integer '' B Pressed? ( NEW ) dim LightAmbient(0 to 3) as single => {0.5, 0.5, 0.5, 1.0} '' Ambient Light Values dim LightDiffuse(0 to 3) as single => {1.0, 1.0, 1.0, 1.0} '' Diffuse Light Values dim LightPosition(0 to 3) as single => {0.0, 0.0, 2.0, 1.0} '' Light Position dim xrot as single '' X Rotation dim yrot as single '' Y Rotation dim xspeed as single '' X Rotation Speed dim yspeed as single '' Y Rotation Speed dim z as single = -5.0 '' Depth Into The Screen screen 18, 16, , 2 '' ReSizeGLScene glViewport 0, 0, 640, 480 '' Reset The Current Viewport glMatrixMode GL_PROJECTION '' Select The Projection Matrix glLoadIdentity '' Reset The Projection Matrix gluPerspective 45.0, 640.0/480.0, 0.1, 100.0 '' Calculate The Aspect Ratio Of The Window glMatrixMode GL_MODELVIEW '' Select The Modelview Matrix glLoadIdentity '' Reset The Modelview Matrix '' Jump To Texture Loading Routine if LoadGLTextures() = false then end 1 '' If Texture Didn't Load Quit end if '' All Setup For OpenGL Goes Here glEnable GL_TEXTURE_2D '' Enable Texture Mapping glShadeModel GL_SMOOTH '' Enable Smooth Shading glClearColor 0.0, 0.0, 0.0, 0.5 '' Black Background glClearDepth 1.0 '' Depth Buffer Setup glEnable GL_DEPTH_TEST '' Enables Depth Testing glDepthFunc GL_LEQUAL '' The Type Of Depth Testing To Do glHint GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST '' Really Nice Perspective Calculations glLightfv GL_LIGHT1, GL_AMBIENT, @LightAmbient(0) '' Setup The Ambient Light glLightfv GL_LIGHT1, GL_DIFFUSE, @LightDiffuse(0) '' Setup The Diffuse Light glLightfv GL_LIGHT1, GL_POSITION, @LightPosition(0) '' Position The Light glEnable GL_LIGHT1 '' Enable Light One glColor4f 1.0, 1.0, 1.0, 0.5 '' Full Brightness. 50% Alpha glBlendFunc GL_SRC_ALPHA, GL_ONE '' Set The Blending Function For Translucency do glClear GL_COLOR_BUFFER_BIT or GL_DEPTH_BUFFER_BIT '' Clear Screen And Depth Buffer glLoadIdentity '' Reset The View glTranslatef 0.0, 0.0, z glRotatef xrot, 1.0, 0.0, 0.0 '' Rotate On The X Axis By xrot glRotatef yrot, 0.0, 1.0, 0.0 '' Rotate On The Y Axis By yrot glBindTexture GL_TEXTURE_2D, texture(filter) '' Select A Texture Based On filter glBegin GL_QUADS '' Start Drawing Quads '' Front Face glNormal3f 0.0, 0.0, 1.0 '' Normal Pointing Towards Viewer glTexCoord2f 0.0, 0.0 : glVertex3f -1.0, -1.0, 1.0 '' Point 1 (Front) glTexCoord2f 1.0, 0.0 : glVertex3f 1.0, -1.0, 1.0 '' Point 2 glTexCoord2f 1.0, 1.0 : glVertex3f 1.0, 1.0, 1.0 '' Point 3 glTexCoord2f 0.0, 1.0 : glVertex3f -1.0, 1.0, 1.0 '' Point 4 '' Back Face glNormal3f 0.0, 0.0, -1.0 '' Normal Pointing Away From Viewer glTexCoord2f 1.0, 0.0 : glVertex3f -1.0, -1.0, -1.0 '' Point 1 (Back) glTexCoord2f 1.0, 1.0 : glVertex3f -1.0, 1.0, -1.0 '' Point 2 glTexCoord2f 0.0, 1.0 : glVertex3f 1.0, 1.0, -1.0 '' Point 3 glTexCoord2f 0.0, 0.0 : glVertex3f 1.0, -1.0, -1.0 '' Point 4 '' Top Face glNormal3f 0.0, 1.0, 0.0 '' Normal Pointing Up glTexCoord2f 0.0, 1.0 : glVertex3f -1.0, 1.0, -1.0 '' (Top) glTexCoord2f 0.0, 0.0 : glVertex3f -1.0, 1.0, 1.0 glTexCoord2f 1.0, 0.0 : glVertex3f 1.0, 1.0, 1.0 glTexCoord2f 1.0, 1.0 : glVertex3f 1.0, 1.0, -1.0 '' Bottom Face glNormal3f 0.0, -1.0, 0.0 '' Normal Pointing Down glTexCoord2f 1.0, 1.0 : glVertex3f -1.0, -1.0, -1.0 '' (Bottom) glTexCoord2f 0.0, 1.0 : glVertex3f 1.0, -1.0, -1.0 glTexCoord2f 0.0, 0.0 : glVertex3f 1.0, -1.0, 1.0 glTexCoord2f 1.0, 0.0 : glVertex3f -1.0, -1.0, 1.0 '' Right face glNormal3f 1.0, 0.0, 0.0 '' Normal Pointing Right glTexCoord2f 1.0, 0.0 : glVertex3f 1.0, -1.0, -1.0 '' (Right) glTexCoord2f 1.0, 1.0 : glVertex3f 1.0, 1.0, -1.0 glTexCoord2f 0.0, 1.0 : glVertex3f 1.0, 1.0, 1.0 glTexCoord2f 0.0, 0.0 : glVertex3f 1.0, -1.0, 1.0 '' Left Face glNormal3f -1.0, 0.0, 0.0 '' Normal Pointing Left glTexCoord2f 0.0, 0.0 : glVertex3f -1.0, -1.0, -1.0 '' (Left) glTexCoord2f 1.0, 0.0 : glVertex3f -1.0, -1.0, 1.0 glTexCoord2f 1.0, 1.0 : glVertex3f -1.0, 1.0, 1.0 glTexCoord2f 0.0, 1.0 : glVertex3f -1.0, 1.0, -1.0 glEnd '' Done Drawing Quads xrot = xrot + xspeed '' Add xspeed To xrot yrot = yrot + yspeed '' Add yspeed To yrot '' Keyboard handlers if MULTIKEY(FB.SC_L) and not lp then '' L Key down lp = true light = not light '' toggle light on /off if (not light) then glDisable(GL_LIGHTING) '' disable lighting else glEnable(GL_LIGHTING) '' enable lighting end if end if if MULTIKEY(FB.SC_L) = 0 then lp = false '' L key up if MULTIKEY(FB.SC_F) and not fp then '' F Key down fp = true filter += 1 '' Cycle filter 0 -> 1 -> 2 if (filter > 2) then filter = 0 '' 2 -> 0 end if if MULTIKEY(FB.SC_F) = 0 then fp = false '' F Key Up '' Blending Code Starts Here if MULTIKEY(FB.SC_B) and not blendpressed then '' B Key down blendpressed = true blend = not blend '' toggle blending On/Off if blend then glEnable(GL_BLEND) '' Turn Blending On glDisable(GL_DEPTH_TEST) '' Turn Depth Testing Off else glDisable(GL_BLEND) '' Turn Blending Off glEnable(GL_DEPTH_TEST) '' Turn Depth Testing On end if end if if MULTIKEY(FB.SC_B) = 0 then blendpressed = false '' B Key up '' Blending Code Ends Here if MULTIKEY(FB.SC_PAGEUP) then z-=0.02 '' If Page Up is Being Pressed, Move Into The Screen if MULTIKEY(FB.SC_PAGEDOWN) then z+=0.02 '' If Page Down is Being Pressed, Move Towards The Viewer if MULTIKEY(FB.SC_UP) then xspeed-=0.01 '' If Up Arrow is Being Pressed, Decrease xspeed if MULTIKEY(FB.SC_DOWN) then xspeed+=0.01 '' If Down Arrow Being Pressed, Increase xspeed if MULTIKEY(FB.SC_RIGHT) then yspeed+=0.01 '' If Right Arrow Being Pressed, Increase yspeed if MULTIKEY(FB.SC_LEFT) then yspeed-=0.01 '' If Left Arrow Being Pressed, Decrease yspeed flip '' flip or crash loop while MULTIKEY(FB.SC_ESCAPE) = 0 'Empty keyboard buffer while inkey <> "": wend glDeleteTextures 3, @texture(0) end '' Load Bitmaps And Convert To Textures function LoadGLTextures() as integer dim Status as integer = false '' Status Indicator dim TextureImage(0) as BITMAP_RGBImageRec ptr '' Create Storage Space For The Texture ' Load The Bitmap, Check For Errors, If Bitmap's Not Found Quit TextureImage(0) = LoadBMP(exepath + "/data/Glass.bmp") if TextureImage(0) then glGenTextures 3, @texture(0) '' Create The Texture if texture(0) <> 0 and texture(1) <> 0 and texture(2) <> 0 then ' Create Nearest Filtered Texture glBindTexture GL_TEXTURE_2D, texture(0) glTexParameteri GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST glTexParameteri GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST glTexImage2D GL_TEXTURE_2D, 0, 3, TextureImage(0)->sizeX, TextureImage(0)->sizeY, 0, GL_RGB, GL_UNSIGNED_BYTE, TextureImage(0)->buffer ' Create Linear Filtered Texture glBindTexture GL_TEXTURE_2D, texture(1) glTexParameteri GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR glTexParameteri GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR glTexImage2D GL_TEXTURE_2D, 0, 3, TextureImage(0)->sizeX, TextureImage(0)->sizeY, 0, GL_RGB, GL_UNSIGNED_BYTE, TextureImage(0)->buffer ' Create MipMapped Texture glBindTexture GL_TEXTURE_2D, texture(2) glTexParameteri GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR glTexParameteri GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST if gluBuild2DMipmaps(GL_TEXTURE_2D, 3, TextureImage(0)->sizeX, TextureImage(0)->sizeY, GL_RGB, GL_UNSIGNED_BYTE, TextureImage(0)->buffer) = 0 then Status = true '' All three textures are ready end if end if end if if TextureImage(0) then '' If Texture Exists if TextureImage(0)->buffer then '' If Texture Image Exist deallocate(TextureImage(0)->buffer) '' Free The Texture Image Memory end if deallocate(TextureImage(0)) '' Free The Image Structure end if if Status = false then glDeleteTextures 3, @texture(0) texture(0) = 0 texture(1) = 0 texture(2) = 0 end if return Status '' Return The Status end function '' End of lesson08.bas