Source

gltut / Tut 08 Getting Oriented / CameraRelative.cpp

Jason McKesson 6feca88 



Jason McKesson da7c819 
Jason McKesson 74c4b9b 
Jason McKesson 6feca88 














































































































Jason McKesson 0d40f37 
Jason McKesson 6feca88 



Jason McKesson 0d40f37 

Jason McKesson 6feca88 
Jason McKesson 0d40f37 
Jason McKesson 6feca88 

















































































































































































Jason McKesson f314aea 
#include <string>
#include <vector>
#include <stack>
#include <math.h>
#include <stdio.h>
#include <glload/gl_3_3.h>
#include <GL/freeglut.h>
#include "../framework/framework.h"
#include "../framework/Mesh.h"
#include "../framework/MatrixStack.h"
#include <glm/glm.hpp>
#include <glm/gtc/type_ptr.hpp>
#include <glm/gtc/quaternion.hpp>

#define ARRAY_COUNT( array ) (sizeof( array ) / (sizeof( array[0] ) * (sizeof( array ) != sizeof(void*) || sizeof( array[0] ) <= sizeof(void*))))

GLuint theProgram;
GLuint positionAttrib;
GLuint colorAttrib;

GLuint modelToCameraMatrixUnif;
GLuint cameraToClipMatrixUnif;
GLuint baseColorUnif;

glm::mat4 cameraToClipMatrix(0.0f);

float CalcFrustumScale(float fFovDeg)
{
	const float degToRad = 3.14159f * 2.0f / 360.0f;
	float fFovRad = fFovDeg * degToRad;
	return 1.0f / tan(fFovRad / 2.0f);
}

const float fFrustumScale = CalcFrustumScale(20.0f);

void InitializeProgram()
{
	std::vector<GLuint> shaderList;

	shaderList.push_back(Framework::LoadShader(GL_VERTEX_SHADER, "PosColorLocalTransform.vert"));
	shaderList.push_back(Framework::LoadShader(GL_FRAGMENT_SHADER, "ColorMultUniform.frag"));

	theProgram = Framework::CreateProgram(shaderList);

	positionAttrib = glGetAttribLocation(theProgram, "position");
	colorAttrib = glGetAttribLocation(theProgram, "color");

	modelToCameraMatrixUnif = glGetUniformLocation(theProgram, "modelToCameraMatrix");
	cameraToClipMatrixUnif = glGetUniformLocation(theProgram, "cameraToClipMatrix");
	baseColorUnif = glGetUniformLocation(theProgram, "baseColor");

	float fzNear = 1.0f; float fzFar = 600.0f;

	cameraToClipMatrix[0].x = fFrustumScale;
	cameraToClipMatrix[1].y = fFrustumScale;
	cameraToClipMatrix[2].z = (fzFar + fzNear) / (fzNear - fzFar);
	cameraToClipMatrix[2].w = -1.0f;
	cameraToClipMatrix[3].z = (2 * fzFar * fzNear) / (fzNear - fzFar);

	glUseProgram(theProgram);
	glUniformMatrix4fv(cameraToClipMatrixUnif, 1, GL_FALSE, glm::value_ptr(cameraToClipMatrix));
	glUseProgram(0);
}

Framework::Mesh *g_pShip = NULL;
Framework::Mesh *g_pPlane = NULL;

//Called after the window and OpenGL are initialized. Called exactly once, before the main loop.
void init()
{
	InitializeProgram();

	try
	{
		g_pShip = new Framework::Mesh("Ship.xml");
		g_pPlane = new Framework::Mesh("UnitPlane.xml");
	}
	catch(std::exception &except)
	{
		printf(except.what());
	}


	glEnable(GL_CULL_FACE);
	glCullFace(GL_BACK);
	glFrontFace(GL_CW);

	glEnable(GL_DEPTH_TEST);
	glDepthMask(GL_TRUE);
	glDepthFunc(GL_LEQUAL);
	glDepthRange(0.0f, 1.0f);
}

struct GimbalAngles
{
	GimbalAngles()
		: fAngleX(0.0f)
		, fAngleY(0.0f)
		, fAngleZ(0.0f)
	{}

	float fAngleX;
	float fAngleY;
	float fAngleZ;
};

GimbalAngles g_angles;
static glm::vec3 g_camTarget(0.0f, 10.0f, 0.0f);
static glm::fquat g_orientation(1.0f, 0.0f, 0.0f, 0.0f);

//In spherical coordinates.
static glm::vec3 g_sphereCamRelPos(90.0f, 0.0f, 66.0f);

glm::vec3 ResolveCamPosition()
{
	Framework::MatrixStack tempMat;

	float phi = Framework::DegToRad(g_sphereCamRelPos.x);
	float theta = Framework::DegToRad(g_sphereCamRelPos.y + 90.0f);

	float fSinTheta = sinf(theta);
	float fCosTheta = cosf(theta);
	float fCosPhi = cosf(phi);
	float fSinPhi = sinf(phi);

	glm::vec3 dirToCamera(fSinTheta * fCosPhi, fCosTheta, fSinTheta * fSinPhi);
	return (dirToCamera * g_sphereCamRelPos.z) + g_camTarget;
}

glm::mat4 CalcLookAtMatrix(const glm::vec3 &cameraPt, const glm::vec3 &lookPt, const glm::vec3 &upPt)
{
	glm::vec3 lookDir = glm::normalize(lookPt - cameraPt);
	glm::vec3 upDir = glm::normalize(upPt);

	glm::vec3 rightDir = glm::normalize(glm::cross(lookDir, upDir));
	glm::vec3 perpUpDir = glm::cross(rightDir, lookDir);

	glm::mat4 rotMat(1.0f);
	rotMat[0] = glm::vec4(rightDir, 0.0f);
	rotMat[1] = glm::vec4(perpUpDir, 0.0f);
	rotMat[2] = glm::vec4(-lookDir, 0.0f);

	rotMat = glm::transpose(rotMat);

	glm::mat4 transMat(1.0f);
	transMat[3] = glm::vec4(-cameraPt, 1.0f);

	return rotMat * transMat;
}


//Called to update the display.
//You should call glutSwapBuffers after all of your rendering to display what you rendered.
//If you need continuous updates of the screen, call glutPostRedisplay() at the end of the function.
void display()
{
	glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
	glClearDepth(1.0f);
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

	Framework::MatrixStack currMatrix;
	const glm::vec3 &camPos = ResolveCamPosition();
	currMatrix.SetMatrix(CalcLookAtMatrix(camPos, g_camTarget, glm::vec3(0.0f, 1.0f, 0.0f)));

	glUseProgram(theProgram);

	{
		Framework::MatrixStackPusher stack(currMatrix);
		currMatrix.Scale(100.0f, 1.0f, 100.0f);

		glUniform4f(baseColorUnif, 0.2f, 0.5f, 0.2f, 1.0f);
		glUniformMatrix4fv(modelToCameraMatrixUnif, 1, GL_FALSE, glm::value_ptr(currMatrix.Top()));

		g_pPlane->Render();
	}

	{
		Framework::MatrixStackPusher stack(currMatrix);
		currMatrix.Translate(g_camTarget);
		currMatrix.ApplyMatrix(glm::mat4_cast(g_orientation));
		currMatrix.RotateX(-90);

		//Set the base color for this object.
		glUniform4f(baseColorUnif, 1.0f, 1.0f, 1.0f, 1.0f);
		glUniformMatrix4fv(modelToCameraMatrixUnif, 1, GL_FALSE, glm::value_ptr(currMatrix.Top()));

		g_pShip->Render("tint");
	}

	glUseProgram(0);

	glutSwapBuffers();
	glutPostRedisplay();
}

//Called whenever the window is resized. The new window size is given, in pixels.
//This is an opportunity to call glViewport or glScissor to keep up with the change in size.
void reshape (int w, int h)
{
	cameraToClipMatrix[0].x = fFrustumScale * (h / (float)w);
	cameraToClipMatrix[1].y = fFrustumScale;

	glUseProgram(theProgram);
	glUniformMatrix4fv(cameraToClipMatrixUnif, 1, GL_FALSE, glm::value_ptr(cameraToClipMatrix));
	glUseProgram(0);

	glViewport(0, 0, (GLsizei) w, (GLsizei) h);
}

#define SMALL_ANGLE_INCREMENT 9.0f

enum OffsetRelative
{
	MODEL_RELATIVE,
	WORLD_RELATIVE,
	CAMERA_RELATIVE,

	NUM_RELATIVES,
};

static int g_iOffset = MODEL_RELATIVE;

void OffsetOrientation(const glm::vec3 &_axis, float fAngDeg)
{
	float fAngRad = Framework::DegToRad(fAngDeg);

	glm::vec3 axis = glm::normalize(_axis);

	axis = axis * sinf(fAngRad / 2.0f);
	float scalar = cosf(fAngRad / 2.0f);

	glm::fquat offset(scalar, axis.x, axis.y, axis.z);

	switch(g_iOffset)
	{
	case MODEL_RELATIVE:
		g_orientation = g_orientation * offset;
		break;
	case WORLD_RELATIVE:
		g_orientation = offset * g_orientation;
		break;
	case CAMERA_RELATIVE:
		{
			const glm::vec3 &camPos = ResolveCamPosition();
			const glm::mat4 &camMat = CalcLookAtMatrix(camPos, g_camTarget, glm::vec3(0.0f, 1.0f, 0.0f));

			glm::fquat viewQuat = glm::quat_cast(camMat);
			glm::fquat invViewQuat = glm::conjugate(viewQuat);

			const glm::fquat &worldQuat = (invViewQuat * offset * viewQuat);
			g_orientation = worldQuat * g_orientation;
		}
		break;
	}

	g_orientation = glm::normalize(g_orientation);
}


//Called whenever a key on the keyboard was pressed.
//The key is given by the ''key'' parameter, which is in ASCII.
//It's often a good idea to have the escape key (ASCII value 27) call glutLeaveMainLoop() to 
//exit the program.
void keyboard(unsigned char key, int x, int y)
{
	switch (key)
	{
	case 27:
		glutLeaveMainLoop();
		break;
	case 'w': OffsetOrientation(glm::vec3(1.0f, 0.0f, 0.0f), SMALL_ANGLE_INCREMENT); break;
	case 's': OffsetOrientation(glm::vec3(1.0f, 0.0f, 0.0f), -SMALL_ANGLE_INCREMENT); break;

	case 'a': OffsetOrientation(glm::vec3(0.0f, 0.0f, 1.0f), SMALL_ANGLE_INCREMENT); break;
	case 'd': OffsetOrientation(glm::vec3(0.0f, 0.0f, 1.0f), -SMALL_ANGLE_INCREMENT); break;

	case 'q': OffsetOrientation(glm::vec3(0.0f, 1.0f, 0.0f), SMALL_ANGLE_INCREMENT); break;
	case 'e': OffsetOrientation(glm::vec3(0.0f, 1.0f, 0.0f), -SMALL_ANGLE_INCREMENT); break;
	case 32:
		g_iOffset += 1;
		g_iOffset = g_iOffset % NUM_RELATIVES;
		{
			switch(g_iOffset)
			{
			case MODEL_RELATIVE: printf("Model Relative\n"); break;
			case WORLD_RELATIVE: printf("World Relative\n"); break;
			case CAMERA_RELATIVE: printf("Camera Relative\n"); break;
			}
		}
		break;
	case 'i': g_sphereCamRelPos.y -= 11.25f; break;
	case 'k': g_sphereCamRelPos.y += 11.25f; break;
	case 'j': g_sphereCamRelPos.x -= 11.25f; break;
	case 'l': g_sphereCamRelPos.x += 11.25f; break;
	case 'I': g_sphereCamRelPos.y -= 1.125f; break;
	case 'K': g_sphereCamRelPos.y += 1.125f; break;
	case 'J': g_sphereCamRelPos.x -= 1.125f; break;
	case 'L': g_sphereCamRelPos.x += 1.125f; break;
	}

	g_sphereCamRelPos.y = glm::clamp(g_sphereCamRelPos.y, -78.75f, 10.0f);
}


unsigned int defaults(unsigned int displayMode, int &width, int &height) {return displayMode;}
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