From f05e7eba9598f1afaeed600a016afda5d426e610 Mon Sep 17 00:00:00 2001 From: Brian Paul Date: Tue, 1 Aug 2006 20:03:05 +0000 Subject: [PATCH] code to draw engine block --- progs/demos/engine.c | 216 ++++++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 205 insertions(+), 11 deletions(-) diff --git a/progs/demos/engine.c b/progs/demos/engine.c index 8ef7346..143b02a 100644 --- a/progs/demos/engine.c +++ b/progs/demos/engine.c @@ -47,6 +47,7 @@ typedef struct GLuint CrankList; GLuint ConnRodList; GLuint PistonList; + GLuint BlockList; } Engine; @@ -80,6 +81,7 @@ typedef struct GLboolean UseLists; GLboolean DrawBox; GLboolean ShowInfo; + GLboolean ShowBlock; } RenderInfo; @@ -87,9 +89,10 @@ static GLUquadric *Q; static GLfloat Theta = 0.0; -static GLfloat PistonColor[4] = { 1.0, 0.5, 0.5, 1.0 }; -static GLfloat ConnRodColor[4] = { 0.7, 1.0, 0.7, 1.0 }; -static GLfloat CrankshaftColor[4] = { 0.7, 0.7, 1.0, 1.0 }; +static const GLfloat PistonColor[4] = { 1.0, 0.5, 0.5, 1.0 }; +static const GLfloat ConnRodColor[4] = { 0.7, 1.0, 0.7, 1.0 }; +static const GLfloat CrankshaftColor[4] = { 0.7, 0.7, 1.0, 1.0 }; +static const GLfloat BlockColor[4] = {0.8, 0.8, 0.8, 0.75 }; static GLuint TextureObj; static GLint WinWidth = 800, WinHeight = 500; @@ -113,7 +116,7 @@ static Engine Engines[NUM_ENGINES] = 0.25, /* CrankPinRadius */ 0.3, /* CrankJournalRadius */ 0.4, /* CrankJournalLength */ - 1.3, /* ConnectingRodLength */ + 1.5, /* ConnectingRodLength */ 0.1 /* ConnectingRodThickness */ }, { @@ -129,7 +132,7 @@ static Engine Engines[NUM_ENGINES] = 0.25, /* CrankPinRadius */ 0.3, /* CrankJournalRadius */ 0.4, /* CrankJournalLength */ - 1.3, /* ConnectingRodLength */ + 1.5, /* ConnectingRodLength */ 0.1 /* ConnectingRodThickness */ }, { @@ -145,7 +148,7 @@ static Engine Engines[NUM_ENGINES] = 0.25, /* CrankPinRadius */ 0.3, /* CrankJournalRadius */ 0.4, /* CrankJournalLength */ - 1.3, /* ConnectingRodLength */ + 1.5, /* ConnectingRodLength */ 0.1 /* ConnectingRodThickness */ } }; @@ -180,6 +183,7 @@ InitRenderInfo(RenderInfo *render) render->Texture = GL_FALSE; render->DrawBox = GL_FALSE; render->ShowInfo = GL_TRUE; + render->ShowBlock = GL_FALSE; render->UseLists = GL_FALSE; } @@ -190,6 +194,9 @@ InitRenderInfo(RenderInfo *render) static void SetRenderState(RenderMode mode) { + static const GLfloat gray2[4] = { 0.2, 0.2, 0.2, 1.0 }; + static const GLfloat gray4[4] = { 0.4, 0.4, 0.4, 1.0 }; + /* defaults */ glDisable(GL_LIGHTING); glDisable(GL_TEXTURE_2D); @@ -198,6 +205,7 @@ SetRenderState(RenderMode mode) glPolygonMode(GL_FRONT_AND_BACK, GL_FILL); glDisable(GL_TEXTURE_GEN_S); glDisable(GL_TEXTURE_GEN_T); + glLightModelfv(GL_LIGHT_MODEL_AMBIENT, gray2); switch (mode) { case LIT: @@ -214,6 +222,7 @@ SetRenderState(RenderMode mode) glEnable(GL_TEXTURE_2D); glEnable(GL_TEXTURE_GEN_S); glEnable(GL_TEXTURE_GEN_T); + glLightModelfv(GL_LIGHT_MODEL_AMBIENT, gray4); break; default: ; @@ -270,6 +279,19 @@ PistonShaftPosition(const Engine *eng, int piston) /** + * Compute distance between two adjacent pistons + */ +static float +PistonSpacing(const Engine *eng) +{ + const int pistonsPerCrank = eng->Pistons / eng->Cranks; + const float z0 = PistonShaftPosition(eng, 0); + const float z1 = PistonShaftPosition(eng, pistonsPerCrank); + return z1 - z0; +} + + +/** * (x0, y0) = position of big end on crankshaft * (x1, y1) = position of small end on piston */ @@ -518,6 +540,144 @@ DrawPositionedConnectingRod(const Engine *eng, float crankAngle) /** + * Draw a square with a hole in middle. + */ +static void +SquareWithHole(float squareSize, float holeRadius) +{ + int i; + glBegin(GL_QUAD_STRIP); + glNormal3f(0, 0, 1); + for (i = 0; i <= 360; i += 5) { + const float x1 = holeRadius * cos(DEG_TO_RAD(i)); + const float y1 = holeRadius * sin(DEG_TO_RAD(i)); + float x2, y2; + if (i > 315 || i <= 45) { + x2 = squareSize; + y2 = squareSize * tan(DEG_TO_RAD(i)); + } + else if (i > 45 && i <= 135) { + x2 = -squareSize * tan(DEG_TO_RAD(i - 90)); + y2 = squareSize; + } + else if (i > 135 && i <= 225) { + x2 = -squareSize; + y2 = -squareSize * tan(DEG_TO_RAD(i-180)); + } + else if (i > 225 && i <= 315) { + x2 = squareSize * tan(DEG_TO_RAD(i - 270)); + y2 = -squareSize; + } + glVertex2f(x1, y1); /* inner circle */ + glVertex2f(x2, y2); /* outer square */ + } + glEnd(); +} + + +/** + * Draw block with hole through middle. + * Hole is centered on Z axis. + * Bottom of block is at z=0, top of block is at z = blockHeight. + * index is in [0, count - 1] to determine which block faces are drawn. + */ +static void +DrawBlockWithHole(float blockSize, float blockHeight, float holeRadius, + int index, int count) +{ + const int slices = 30, stacks = 4; + const float x = blockSize; + const float y = blockSize; + const float z0 = 0; + const float z1 = blockHeight; + + assert(index < count); + assert(Q); + gluQuadricOrientation(Q, GLU_INSIDE); + + glBegin(GL_QUADS); + /* +X face */ + glNormal3f(1, 0, 0); + glVertex3f( x, -y, z0); + glVertex3f( x, y, z0); + glVertex3f( x, y, z1); + glVertex3f( x, -y, z1); + /* -X face */ + glNormal3f(-1, 0, 0); + glVertex3f(-x, -y, z1); + glVertex3f(-x, y, z1); + glVertex3f(-x, y, z0); + glVertex3f(-x, -y, z0); + if (index == 0) { + /* +Y face */ + glNormal3f(0, 1, 0); + glVertex3f(-x, y, z1); + glVertex3f( x, y, z1); + glVertex3f( x, y, z0); + glVertex3f(-x, y, z0); + } + if (index == count - 1) { + /* -Y face */ + glNormal3f(0, -1, 0); + glVertex3f(-x, -y, z0); + glVertex3f( x, -y, z0); + glVertex3f( x, -y, z1); + glVertex3f(-x, -y, z1); + } + glEnd(); + + /* cylinder / hole */ + gluCylinder(Q, holeRadius, holeRadius, blockHeight, slices, stacks); + + /* face at z0 */ + glPushMatrix(); + glRotatef(180, 1, 0, 0); + SquareWithHole(blockSize, holeRadius); + glPopMatrix(); + + /* face at z1 */ + glTranslatef(0, 0, z1); + SquareWithHole(blockSize, holeRadius); + + gluQuadricOrientation(Q, GLU_OUTSIDE); +} + + +/** + * Draw the engine block. + */ +static void +DrawEngineBlock(const Engine *eng) +{ + const float blockHeight = eng->Throw + 1.5 * eng->PistonHeight; + const float cylRadius = 1.01 * eng->PistonRadius; + const float blockSize = 0.5 * PistonSpacing(eng); + const int pistonsPerCrank = eng->Pistons / eng->Cranks; + int i; + + for (i = 0; i < eng->Pistons; i++) { + const float z = PistonShaftPosition(eng, i); + const int crank = i / pistonsPerCrank; + int k; + + glPushMatrix(); + glTranslatef(0, 0, z); + + /* additional rotation for kth piston per crank */ + k = i % pistonsPerCrank; + glRotatef(k * -eng->V_Angle, 0, 0, 1); + + /* the block */ + glRotatef(-90, 1, 0, 0); + glTranslatef(0, 0, eng->Throw * 2); + DrawBlockWithHole(blockSize, blockHeight, cylRadius, + crank, eng->Cranks); + glPopMatrix(); + } +} + + +/** * Generate display lists for engine parts. */ static void @@ -538,6 +698,11 @@ GenerateDisplayLists(Engine *eng) glNewList(eng->PistonList, GL_COMPILE); DrawPiston(eng); glEndList(); + + eng->BlockList = glGenLists(1); + glNewList(eng->BlockList, GL_COMPILE); + DrawEngineBlock(eng); + glEndList(); } @@ -553,10 +718,11 @@ FreeDisplayLists(Engine *eng) eng->ConnRodList = 0; glDeleteLists(eng->PistonList, 1); eng->PistonList = 0; + glDeleteLists(eng->BlockList, 1); + eng->BlockList = 0; } - /** * Draw complete engine. * \param eng description of engine to draw @@ -602,10 +768,32 @@ DrawEngine(const Engine *eng, float crankAngle) glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, ConnRodColor); glColor4fv(ConnRodColor); DrawPositionedConnectingRod(eng, rot); - glPopMatrix(); } + if (Render.ShowBlock) { + const GLboolean blend = glIsEnabled(GL_BLEND); + + glDepthMask(GL_FALSE); + if (!blend) { + glEnable(GL_BLEND); + } + glEnable(GL_CULL_FACE); + + glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, BlockColor); + glColor4fv(BlockColor); + if (eng->CrankList) + glCallList(eng->BlockList); + else + DrawEngineBlock(eng); + + glDisable(GL_CULL_FACE); + glDepthMask(GL_TRUE); + if (!blend) { + glDisable(GL_BLEND); + } + } + glPopMatrix(); } @@ -745,9 +933,9 @@ Draw(void) glPushMatrix(); glTranslatef(0, -0.75, 0); - DrawEngine(Engines + CurEngine, Theta); if (Render.DrawBox) DrawBox(); + DrawEngine(Engines + CurEngine, Theta); glPopMatrix(); glPopMatrix(); @@ -900,6 +1088,12 @@ OptDisplayLists(void) } static void +OptShowBlock(void) +{ + Render.ShowBlock = !Render.ShowBlock; +} + +static void OptShowInfo(void) { Render.ShowInfo = !Render.ShowInfo; @@ -940,8 +1134,9 @@ static const MenuInfo MenuItems[] = { { "Change Engine", 'e', OptChangeEngine }, { "Rendering Style", 'm', OptRenderMode }, { "Display Lists", 'd', OptDisplayLists }, + { "Show Block", 'b', OptShowBlock }, { "Show Info", 'i', OptShowInfo }, - { "Show Box", 'b', OptShowBox }, + { "Show Box", 'x', OptShowBox }, { "Exit", 27, OptExit }, { NULL, 'r', OptRotate }, { NULL, 0, NULL } @@ -1070,7 +1265,6 @@ Init(void) glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, specular); glEnable(GL_NORMALIZE); - glBlendFunc(GL_SRC_ALPHA, GL_ZERO); glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); InitViewInfo(&View); -- 2.7.4