# OpenGL Golden Rectangle!

## Recommended Posts

97

Hello guys.I need help.Really.. I have homework about golden rectangle.I didn't know anything about this homework.If i won't do this i won't pass this lesson just help me please.

I need golden rectangle codes in opengl

I ATTACHED MY HOMEWORK
Edited by sweeneyt0dd

##### Share on other sites
haegarr    7372

Forum rules are quite clear about homework: Its your job to do it! We may help, but we don't solve it for you. So ... what is your problem in detail? Understanding the golden ratio? Understanding the assignment text? Knowledge of OpenGL? Knowledge of GLUT?

(Is this sentence complete?) What have you done / tried so far?

##### Share on other sites
97

Forum rules are quite clear about homework: Its your job to do it! We may help, but we don't solve it for you. So ... what is your problem in detail? Understanding the golden ratio? Understanding the assignment text? Knowledge of OpenGL? Knowledge of GLUT?

(Is this sentence complete?) What have you done / tried so far?

dude..I'm new in this lesson in class.Just want golden rectangle codes likes

#include "stdafx.h"
#include <glut.h>
#include <math.h>

GLfloat G = (1 + (sqrt(float (5))))/2;

GLfloat gla1 = 0;
GLfloat glb1 = 0;
GLfloat gla2;
GLfloat glb2;

bool flip = true;

void genNextRect(void)
{
if (flip == false)
{
gla2 = gla2;
glb2 = gla2/G;

}
else
{
glb2 = glb2;
gla2 = gla2/G;

}
}

void init(void)
{
glClearColor(1.0, 1.0, 1.0, 0.0);
glMatrixMode(GL_PROJECTION);
glOrtho(0.0, 600.0, 0.0, 400.0, -15.0, 15.0);

glMatrixMode(GL_MODELVIEW);
}

void display()
{
glClear(GL_COLOR_BUFFER_BIT);
glLineWidth(4.0);

gla2 = glutGet(GLUT_WINDOW_WIDTH) - 10;
glb2 = glutGet(GLUT_WINDOW_HEIGHT) - 10;

glBegin(GL_LINE_LOOP);
glColor3f(0, 0, 1);
glVertex3f(gla1, glb1, 0);
glVertex3f(gla1, glb2, 0);
glVertex3f(gla2, glb2, 0);
glVertex3f(gla2, glb1, 0);
glEnd();
glutSwapBuffers();
}

void myReshape(GLsizei w, GLsizei h)
{
glViewport(0,0,w,h);
glMatrixMode(GL_PROJECTION);
gluOrtho2D(0.0, w, 0.0, h);
}

int main (int argc, char **argv)
{
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);
glutInitWindowPosition(50, 50);
glutInitWindowSize(600, 500);
glutCreateWindow("");
glutDisplayFunc(display);
glutReshapeFunc(myReshape);
init();
glutMainLoop();

}

##### Share on other sites
fastcall22    10838

If i won't do this i won't pass this lesson just help me please.

... >_>

At this rate, how do you expect to complete the course?

##### Share on other sites
97

If i won't do this i won't pass this lesson just help me please.

... >_>

At this rate, how do you expect to complete the course?

You are right what u want to say.But you don't know why i don't understand nothing this lesson.I didn't go lessons because my family problems. I'm sorry buti just want a help thats all

##### Share on other sites
fastcall22    10838
Okay, don't panic. It's simpler than it looks. Looking at [tt]genNextRect[/tt], it takes the width and height of a rectangle as global parameters, [tt]gla2[/tt] and [tt]glb2[/tt], and sets them to the next smallest golden rectangle. Note, [tt]genNextRect[/tt] assumes the [tt]gla2[/tt] and [tt]glb[/tt] are already a golden rectangle. This is done by taking one of the dimensions and dividing by the golden ratio, which will result in a smaller length. The [tt]flip[/tt] flag determine which dimension to shorten. It is the side with the longest length that is shortened. You will need to keep track of [tt]flip[/tt] such that, when [tt]genNextRect[/tt] is called, that the longest length of the rectangle is shortened. Alternatively, you could remove [tt]flip[/tt] entirely and change the condition in [tt]genNextRect[/tt] to select the longer edge. You may want to check that your rectangle's aspect ratio matches (or is close enough to) the golden ratio after calling [tt]genNextRect[/tt].

After you have called [tt]genNextRect[/tt] you will need to draw it as demonstrated in the [tt]glBegin[/tt]/[tt]glEnd[/tt] block in [tt]display[/tt]. The assignment requires you continue drawing rectangles until the rectangles are too small to display. So, all that's left to complete the assignment is finding the first golden rectangle in the screen and a loop that calls [tt]genNextRect[/tt] and draws the new rectangle until the rectangle is too small to display.

P.S.
Don't panic.
[spoiler]
In pseudo-code, it'd look something like this:
display:
let rectangle be the size of the screen

begin drawing lines
while (area of rectangle) > 1 pixel:
rectangle = genNextRect rectangle

set rectangle color
draw each rectangle edge

end drawing lines

[/spoiler] Edited by fastcall22

##### Share on other sites
97

Okay, don't panic. It's simpler than it looks. Looking at [tt]genNextRect[/tt], it takes the width and height of a rectangle as global parameters, [tt]gla2[/tt] and [tt]glb2[/tt], and sets them to the next smallest golden rectangle. Note, [tt]genNextRect[/tt] assumes the [tt]gla2[/tt] and [tt]glb[/tt] are already a golden rectangle. This is done by taking one of the dimensions and dividing by the golden ratio, which will result in a smaller length. The [tt]flip[/tt] flag determine which dimension to shorten. It is the side with the longest length that is shortened. You will need to keep track of [tt]flip[/tt] such that, when [tt]genNextRect[/tt] is called, that the longest length of the rectangle is shortened. Alternatively, you could remove [tt]flip[/tt] entirely and change the condition in [tt]genNextRect[/tt] to select the longer edge. You may want to check that your rectangle's aspect ratio matches (or is close enough to) the golden ratio after calling [tt]genNextRect[/tt].

After you have called [tt]genNextRect[/tt] you will need to draw it as demonstrated in the [tt]glBegin[/tt]/[tt]glEnd[/tt] block in [tt]display[/tt]. The assignment requires you continue drawing rectangles until the rectangles are too small to display. So, all that's left to complete the assignment is finding the first golden rectangle in the screen and a loop that calls [tt]genNextRect[/tt] and draws the new rectangle until the rectangle is too small to display.

P.S.
Don't panic.
[spoiler]
In pseudo-code, it'd look something like this:

display:
let rectangle be the size of the screen

begin drawing lines
while (area of rectangle) > 1 pixel:
rectangle = genNextRect rectangle

set rectangle color
draw each rectangle edge

end drawing lines

[/spoiler]

thank you very much. I will do this with your help :)

## Create an account

Register a new account

• ### Similar Content

• By Zaphyk
I am developing my engine using the OpenGL 3.3 compatibility profile. It runs as expected on my NVIDIA card and on my Intel Card however when I tried it on an AMD setup it ran 3 times worse than on the other setups. Could this be a AMD driver thing or is this probably a problem with my OGL code? Could a different code standard create such bad performance?

• I'm trying to get some legacy OpenGL code to run with a shader pipeline,
The legacy code uses glVertexPointer(), glColorPointer(), glNormalPointer() and glTexCoordPointer() to supply the vertex information.
I know that it should be using setVertexAttribPointer() etc to clearly define the layout but that is not an option right now since the legacy code can't be modified to that extent.
I've got a version 330 vertex shader to somewhat work:
#version 330 uniform mat4 osg_ModelViewProjectionMatrix; uniform mat4 osg_ModelViewMatrix; layout(location = 0) in vec4 Vertex; layout(location = 2) in vec4 Normal; // Velocity layout(location = 3) in vec3 TexCoord; // TODO: is this the right layout location? out VertexData { vec4 color; vec3 velocity; float size; } VertexOut; void main(void) { vec4 p0 = Vertex; vec4 p1 = Vertex + vec4(Normal.x, Normal.y, Normal.z, 0.0f); vec3 velocity = (osg_ModelViewProjectionMatrix * p1 - osg_ModelViewProjectionMatrix * p0).xyz; VertexOut.velocity = velocity; VertexOut.size = TexCoord.y; gl_Position = osg_ModelViewMatrix * Vertex; } What works is the Vertex and Normal information that the legacy C++ OpenGL code seem to provide in layout location 0 and 2. This is fine.
What I'm not getting to work is the TexCoord information that is supplied by a glTexCoordPointer() call in C++.
Question:
What layout location is the old standard pipeline using for glTexCoordPointer()? Or is this undefined?

Side note: I'm trying to get an OpenSceneGraph 3.4.0 particle system to use custom vertex, geometry and fragment shaders for rendering the particles.

• Hi i am new to this forum  i wanted to ask for help from all of you i want to generate real time terrain using a 32 bit heightmap i am good at c++ and have started learning Opengl as i am very interested in making landscapes in opengl i have looked around the internet for help about this topic but i am not getting the hang of the concepts and what they are doing can some here suggests me some good resources for making terrain engine please for example like tutorials,books etc so that i can understand the whole concept of terrain generation.

• By KarimIO
Hey guys. I'm trying to get my application to work on my Nvidia GTX 970 desktop. It currently works on my Intel HD 3000 laptop, but on the desktop, every bind textures specifically from framebuffers, I get half a second of lag. This is done 4 times as I have three RGBA textures and one depth 32F buffer. I tried to use debugging software for the first time - RenderDoc only shows SwapBuffers() and no OGL calls, while Nvidia Nsight crashes upon execution, so neither are helpful. Without binding it runs regularly. This does not happen with non-framebuffer binds.
GLFramebuffer::GLFramebuffer(FramebufferCreateInfo createInfo) { glGenFramebuffers(1, &fbo); glBindFramebuffer(GL_FRAMEBUFFER, fbo); textures = new GLuint[createInfo.numColorTargets]; glGenTextures(createInfo.numColorTargets, textures); GLenum *DrawBuffers = new GLenum[createInfo.numColorTargets]; for (uint32_t i = 0; i < createInfo.numColorTargets; i++) { glBindTexture(GL_TEXTURE_2D, textures[i]); GLint internalFormat; GLenum format; TranslateFormats(createInfo.colorFormats[i], format, internalFormat); // returns GL_RGBA and GL_RGBA glTexImage2D(GL_TEXTURE_2D, 0, internalFormat, createInfo.width, createInfo.height, 0, format, GL_FLOAT, 0); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); DrawBuffers[i] = GL_COLOR_ATTACHMENT0 + i; glBindTexture(GL_TEXTURE_2D, 0); glFramebufferTexture(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0 + i, textures[i], 0); } if (createInfo.depthFormat != FORMAT_DEPTH_NONE) { GLenum depthFormat; switch (createInfo.depthFormat) { case FORMAT_DEPTH_16: depthFormat = GL_DEPTH_COMPONENT16; break; case FORMAT_DEPTH_24: depthFormat = GL_DEPTH_COMPONENT24; break; case FORMAT_DEPTH_32: depthFormat = GL_DEPTH_COMPONENT32; break; case FORMAT_DEPTH_24_STENCIL_8: depthFormat = GL_DEPTH24_STENCIL8; break; case FORMAT_DEPTH_32_STENCIL_8: depthFormat = GL_DEPTH32F_STENCIL8; break; } glGenTextures(1, &depthrenderbuffer); glBindTexture(GL_TEXTURE_2D, depthrenderbuffer); glTexImage2D(GL_TEXTURE_2D, 0, depthFormat, createInfo.width, createInfo.height, 0, GL_DEPTH_COMPONENT, GL_FLOAT, 0); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); glBindTexture(GL_TEXTURE_2D, 0); glFramebufferTexture(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, depthrenderbuffer, 0); } if (createInfo.numColorTargets > 0) glDrawBuffers(createInfo.numColorTargets, DrawBuffers); else glDrawBuffer(GL_NONE); if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) std::cout << "Framebuffer Incomplete\n"; glBindFramebuffer(GL_FRAMEBUFFER, 0); width = createInfo.width; height = createInfo.height; } // ... // FBO Creation FramebufferCreateInfo gbufferCI; gbufferCI.colorFormats = gbufferCFs.data(); gbufferCI.depthFormat = FORMAT_DEPTH_32; gbufferCI.numColorTargets = gbufferCFs.size(); gbufferCI.width = engine.settings.resolutionX; gbufferCI.height = engine.settings.resolutionY; gbufferCI.renderPass = nullptr; gbuffer = graphicsWrapper->CreateFramebuffer(gbufferCI); // Bind glBindFramebuffer(GL_DRAW_FRAMEBUFFER, fbo); // Draw here... // Bind to textures glActiveTexture(GL_TEXTURE0); glBindTexture(GL_TEXTURE_2D, textures[0]); glActiveTexture(GL_TEXTURE1); glBindTexture(GL_TEXTURE_2D, textures[1]); glActiveTexture(GL_TEXTURE2); glBindTexture(GL_TEXTURE_2D, textures[2]); glActiveTexture(GL_TEXTURE3); glBindTexture(GL_TEXTURE_2D, depthrenderbuffer); Here is an extract of my code. I can't think of anything else to include. I've really been butting my head into a wall trying to think of a reason but I can think of none and all my research yields nothing. Thanks in advance!

• Hi everyone, I've shared my 2D Game Engine source code. It's the result of 4 years working on it (and I still continue improving features ) and I want to share with the community. You can see some videos on youtube and some demo gifs on my twitter account.
This Engine has been developed as End-of-Degree Project and it is coded in Javascript, WebGL and GLSL. The engine is written from scratch.
This is not a professional engine but it's for learning purposes, so anyone can review the code an learn basis about graphics, physics or game engine architecture. Source code on this GitHub repository.
I'm available for a good conversation about Game Engine / Graphics Programming

• 15
• 13
• 15
• 10
• 18