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Diamond-Square trouble

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Hey everyone. I've been reading up on he diamond-square algorithm for terrain and understand, sort of. I dont get how, after you do the first diamond and first square iterations, how you get to the next. How does the algorithm know how many squares there are and also, this is confusing, but what point is the center of what points. Like, say you have a 2d array of points that is 5 by 5. it goes: a b c d e f g h i j k l m n o p q r s t u v w x y How does it know that g is the center of a,b,c,h,m,l,k, and f? How does it find what points' heights to average together to equal another points height?

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The area is still a grid in "mind"... it's only the presentation that renders objects like diamonds. Using simple x,y divisions should provide you with the info you need from each tile.

Alternativly;

Each tile is independent of the rest, can be placed anywhere etc.
But it keeps a list of it's neighbours instead.

Quote:

How does it know that g is the center of a,b,c,h,m,l,k, and f? How does it find what points' heights to average together to equal another points height?

Someone once said - you created it, you should know. :)

Cheers!

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You should try expanding your questions, or at least clearify what you mean.

Cheers,
Robert

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Diamond Square
After each iteration you devide the size of each square by 2. Then (size_of_grid - 1) / square_size = number_of_squares_per_side. The center point basically is one of the corners offset by square_size/2.

Example:

I'll also a 2D array for easier reading and rename your points to indices. Changing the example to a 1D array representation is an exercise for you.

OK, let's start:

The array is:

00 01 02 03 04
10 11 12 13 14
20 21 22 23 24
30 31 32 33 34
40 41 42 43 44

LEVEL 0:
Your fist square is 00, 04, 40, 44. It's center is 22 ((square_size(4) / 2 for both indices). Square size is 4, number of squares per side is (5 - 1) / 4 = 1.

Now you do square_size/2 => 4/2 = square_size = 2.

LEVEL 1:
For the next iteration we get:
square_size = 2
num_squares_per_side = (5 - 1) / 2 = 2

With this the squares in that iteration are:
SQ1: 00, 02, 20, 22 C1: 11
SQ2: 02, 04, 22, 24 C2: 13
SQ3: 20, 22, 40, 42 C3: 31
SQ4: 22, 24, 42, 44 C4: 33

That's it. Keep doing this until square_size = 2, since in the next step you won't get any integer center points.


Caution
Using diamond square for averaging points (e.g. midpoint displacement) you have to make sure all the points needed for averaging have their values assigned yet. This is tricky with a recursive approach so for every level you should first do all the square steps and then all the diamond steps. Otherwise you'd get wrong results since the diamond steps depend on the square steps to fill in the correct values first.

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Its been a while since I implemented this algorithm, but I sort of remember how it goes. As I remember it took a many sheets of paper and much confusion.

As you iterate and recurse through levels, quads, vertices, you only know a few things:

1) current recursion level in your diamond-square descent
2) your starting corner index
3) current quad you're processing as you iterate (through x and z)

Everything else you calculate.

So as you recurse through the levels of division (diamond-square), you calculate the indices of your corners, the width of the quad, the vertices of your corners, the center indices for splitting, the indices of your parent's corners and midpoint, etc.

You could preseed the array with y values from a height map, or look them up as your're subdividing. You have to watch out for corner and edge cases when averaging your neighbors or parents, depending how you implement the height calculations.

I wanted to do it totally algorithmicly so I wrote some noise randomizer classes using boost::random that passes the parents seeds down to each sublevel so I could regenerate the displacements based on just a few early seed values.

Try starting by creating an array that will hold all the verts. So if you wanted to end up with a X square quads terrain patch, you'd create an array of ((X+1) * (X+1) floats, and pre-seed the array with the corner verts and your random heights.

Well, I hope that helps you get started. Its not totally trivial, lots of staring at numbers in the debugger and drawing grids of dots on the page. Keep staring at it, and it will eventually make sense. Start with a small grid and just a few levels of recursion, so its easy to debug. Of course use powers of 2 for the width and you'll get really used to relating the vertex values to the quads they're part of.

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Just a little question:

Did you use a breadth first (complete level first then next level) or a depth first (fully subdivide a square first then advance to its neighbors) approach ?
If you used depth first, how did you handle cases where needed values aren't properly initialized?

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Found some code, but I'm not sure what state its in. I worked on this quite a while ago. Looks like I'm actually not doing this recursively, but rather iterating through the levels. This is in the context of a Terrain object which holds a MultilevelTerrainObject (that can handle lod-ing and edge matchup), which holds multiple TerrainChunk objects, each of which holds multiple VertexGrid objects. Not sure if this is the exact diamond-square algorithm as originally envisioned, but I think its sort of close at the VertexGrid level.



#define VERTEX_INDEX(x, z) (((z) * m_WidthVertices) + (x))

void VertexGrid::generateDiamondSquare(int levels, float3* corners)
{
ostringstream logmsg;
logmsg << "generateDiamondSquare(" << levels << ", (" <<
float3ToString(corners[0]) << ", " <<
float3ToString(corners[1]) << ", " <<
float3ToString(corners[2]) << ", " <<
float3ToString(corners[3]) << ")" << endl;
log(1, logmsg);

m_RandomFloatizer->seed(m_GridSeed);

int totalWidthQuads = 1 << levels;
int totalWidthVertices = totalWidthQuads + 1;
int totalNumVertices = totalWidthVertices * totalWidthVertices;
m_WidthVertices = totalWidthVertices;

// allocate vertex array
m_Vertices = new float3[totalNumVertices];

// set outside corners
// corners[x] -- LeftNear = 0, LeftFar = 1, RightFar = 2, RightNear = 3
int lastVertexIndex = totalWidthVertices - 1;
m_Vertices[VERTEX_INDEX(0, 0)] = corners[LeftNear];
m_Vertices[VERTEX_INDEX(0, lastVertexIndex)] = corners[LeftFar];
m_Vertices[VERTEX_INDEX(lastVertexIndex, lastVertexIndex)] = corners[RightFar];
m_Vertices[VERTEX_INDEX(lastVertexIndex, 0)] = corners[RightNear];

for (int level = 0; level < levels; level++)
{
int numQuadsWide = 1 << level;
int numVerticesWide = numQuadsWide + 1;
int quadWidth = totalWidthQuads / numQuadsWide;
int halfWidth = quadWidth / 2;

// Diamond pass
for (int quadZ = 0; quadZ < numQuadsWide; quadZ++)
{
for (int quadX = 0; quadX < numQuadsWide; quadX++)
{
int leftX = quadX * quadWidth;
int rightX = (quadX + 1) * quadWidth;
int nearZ = quadZ * quadWidth;
int farZ = (quadZ + 1) * quadWidth;

// diamond step - find center of square
// find indices of quad corners - based on level, quadx, quadz
int cornerLeftNear = VERTEX_INDEX(leftX, nearZ);
int cornerLeftFar = VERTEX_INDEX(leftX, farZ);
int cornerRightFar = VERTEX_INDEX(rightX, farZ);
int cornerRightNear = VERTEX_INDEX(rightX, nearZ);
int centerIndex = VERTEX_INDEX(leftX + halfWidth, nearZ + halfWidth);

float centerX = (m_Vertices[cornerLeftNear].x + m_Vertices[cornerRightNear].x) / 2.0f;
float centerZ = (m_Vertices[cornerLeftNear].z + m_Vertices[cornerLeftFar].z) / 2.0f;
float centerY = (( m_Vertices[cornerLeftNear].y +
m_Vertices[cornerLeftNear].y +
m_Vertices[cornerLeftNear].y +
m_Vertices[cornerLeftNear].y) / 4.0f)
+ randomHeightDisplacement(level);
m_Vertices[centerIndex] = float3(centerX, centerY, centerZ);
}
}

// Square pass
for (int quadZ = 0; quadZ < numQuadsWide; quadZ++)
{
for (int quadX = 0; quadX < numQuadsWide; quadX++)
{
int leftX = quadX * quadWidth;
int rightX = (quadX + 1) * quadWidth;
int nearZ = quadZ * quadWidth;
int farZ = (quadZ + 1) * quadWidth;

int cornerLeftNear = VERTEX_INDEX(leftX, nearZ);
int cornerLeftFar = VERTEX_INDEX(leftX, farZ);
int cornerRightFar = VERTEX_INDEX(rightX, farZ);
int cornerRightNear = VERTEX_INDEX(rightX, nearZ);
int centerIndex = VERTEX_INDEX(leftX + halfWidth, nearZ + halfWidth);
float edgeLeftX = m_Vertices[cornerLeftNear].x;
float edgeFarZ = m_Vertices[cornerRightFar].z;
float edgeRightX = m_Vertices[cornerRightFar].x;
float edgeNearZ = m_Vertices[cornerLeftNear].z;

// leftX edge center point
int edgeLeftCenterIndex = VERTEX_INDEX(leftX, nearZ + halfWidth);
int edgeLeftDiamondLeftIndex = ((leftX == 0) ? -1 : VERTEX_INDEX(leftX - halfWidth, nearZ + halfWidth));
int edgeLeftDiamondFarIndex = VERTEX_INDEX(leftX, farZ);
int edgeLeftDiamondRightIndex = centerIndex;
int edgeLeftDiamondNearIndex = VERTEX_INDEX(leftX, nearZ);
float edgeLeftCenterX = edgeLeftX;
float edgeLeftCenterZ = (m_Vertices[cornerLeftNear].z + m_Vertices[cornerLeftFar].z) / 2.0f;
float edgeLeftCenterY;
if (leftX == 0)
{
edgeLeftCenterY = ((m_Vertices[edgeLeftDiamondFarIndex].y +
m_Vertices[edgeLeftDiamondRightIndex].y +
m_Vertices[edgeLeftDiamondNearIndex].y)
/ 3.0f)
+ randomHeightDisplacement(level);
}
else
{
edgeLeftCenterY = ((m_Vertices[edgeLeftDiamondLeftIndex].y +
m_Vertices[edgeLeftDiamondFarIndex].y +
m_Vertices[edgeLeftDiamondRightIndex].y +
m_Vertices[edgeLeftDiamondNearIndex].y)
/ 4.0f)
+ randomHeightDisplacement(level);
}
m_Vertices[edgeLeftCenterIndex] = float3(edgeLeftCenterX, edgeLeftCenterY, edgeLeftCenterZ);

// Far edge center point
int edgeFarCenterIndex = VERTEX_INDEX(leftX + halfWidth, farZ);
int edgeFarDiamondLeftIndex = VERTEX_INDEX(leftX, farZ);
int edgeFarDiamondFarIndex = ((farZ == lastVertexIndex) ? -1 : VERTEX_INDEX(leftX + halfWidth, farZ + halfWidth));
int edgeFarDiamondRightIndex = VERTEX_INDEX(rightX, farZ);
int edgeFarDiamondNearIndex = centerIndex;

float edgeFarCenterX = (m_Vertices[cornerLeftFar].x + m_Vertices[cornerRightFar].z) / 2.0f;;
float edgeFarCenterZ = edgeFarZ;
float edgeFarCenterY;
if (farZ == lastVertexIndex)
{
edgeFarCenterY = (( m_Vertices[edgeFarDiamondLeftIndex].y +
m_Vertices[edgeFarDiamondRightIndex].y +
m_Vertices[edgeFarDiamondNearIndex].y)
/ 3.0f)
+ randomHeightDisplacement(level);
}
else
{
edgeFarCenterY = (( m_Vertices[edgeFarDiamondLeftIndex].y +
m_Vertices[edgeFarDiamondFarIndex].y +
m_Vertices[edgeFarDiamondRightIndex].y +
m_Vertices[edgeFarDiamondNearIndex].y)
/ 4.0f)
+ randomHeightDisplacement(level);
}
m_Vertices[edgeFarCenterIndex] = float3(edgeFarCenterX, edgeFarCenterY, edgeFarCenterZ);

// Right edge center point
int edgeRightCenterIndex = VERTEX_INDEX(rightX, nearZ + halfWidth);
int edgeRightDiamondLeftIndex = centerIndex;
int edgeRightDiamondFarIndex = VERTEX_INDEX(rightX, farZ);
int edgeRightDiamondRightIndex = ((rightX == lastVertexIndex) ? -1 : VERTEX_INDEX(rightX + halfWidth, nearZ + halfWidth));
int edgeRightDiamondNearIndex = VERTEX_INDEX(rightX, nearZ);
float edgeRightCenterX = edgeRightX;
float edgeRightCenterZ = (m_Vertices[cornerRightNear].z + m_Vertices[cornerRightFar].z) / 2.0f;
float edgeRightCenterY;
if (rightX == lastVertexIndex)
{
edgeRightCenterY = ((m_Vertices[edgeRightDiamondLeftIndex].y +
m_Vertices[edgeRightDiamondFarIndex].y +
m_Vertices[edgeRightDiamondNearIndex].y)
/ 3.0f)
+ randomHeightDisplacement(level);
}
else
{
edgeRightCenterY = ((m_Vertices[edgeRightDiamondLeftIndex].y +
m_Vertices[edgeRightDiamondFarIndex].y +
m_Vertices[edgeRightDiamondRightIndex].y +
m_Vertices[edgeRightDiamondNearIndex].y)
/ 4.0f)
+ randomHeightDisplacement(level);
}
m_Vertices[edgeRightCenterIndex] = float3(edgeRightCenterX, edgeRightCenterY, edgeRightCenterZ);

// Near edge center point
int edgeNearCenterIndex = VERTEX_INDEX(leftX + halfWidth, nearZ);
int edgeNearDiamondLeftIndex = VERTEX_INDEX(leftX, nearZ);
int edgeNearDiamondFarIndex = centerIndex;
int edgeNearDiamondRightIndex = VERTEX_INDEX(rightX, nearZ);
int edgeNearDiamondNearIndex = ((nearZ == 0) ? -1 : VERTEX_INDEX(leftX + halfWidth, nearZ - halfWidth));
float edgeNearCenterX = (m_Vertices[cornerLeftNear].x + m_Vertices[cornerRightNear].x) / 2.0f;
float edgeNearCenterZ = edgeNearZ;
float edgeNearCenterY;
if (nearZ == 0)
{
edgeNearCenterY = ((m_Vertices[edgeNearDiamondLeftIndex].y +
m_Vertices[edgeNearDiamondFarIndex].y +
m_Vertices[edgeNearDiamondRightIndex].y)
/ 3.0f)
+ randomHeightDisplacement(level);
}
else
{
edgeNearCenterY = ((m_Vertices[edgeNearDiamondLeftIndex].y +
m_Vertices[edgeNearDiamondFarIndex].y +
m_Vertices[edgeNearDiamondRightIndex].y +
m_Vertices[edgeNearDiamondNearIndex].y)
/ 4.0f)
+ randomHeightDisplacement(level);
}
m_Vertices[edgeNearCenterIndex] = float3(edgeNearCenterX, edgeNearCenterY, edgeNearCenterZ);
}
}
}
}


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Quote:

Did you use a breadth first (complete level first then next level) or a depth first (fully subdivide a square first then advance to its neighbors) approach ?
If you used depth first, how did you handle cases where needed values aren't properly initialized?


Oh, to answer your question it looks pretty much breadth first. Each level is totally filled in before you get to the next.

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I tried again, and just made a 5x5 heightmap as an array and tried to render it... didn't go well. The window comes up but it is blank, nothing is drawn.
code:
heightmap:

float heightmap[5][5] =
{{ '0', '0', '0', '0', '0' },
{ '0', '0', '0', '0', '0' },
{ '0', '0', '0', '0', '0' },
{ '0', '0', '0', '0', '0' },
{ '0', '0', '0', '0', '0' }};



drawglscene:

int DrawGLScene(GLvoid) // Here's Where We Do All The Drawing
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Clear Screen And Depth Buffer
glLoadIdentity(); // Reset The Current Modelview Matrix
glTranslatef(0.0f,0.0f,-5.0f);
glColor3f(0.0f,1.0f,0.1f);
float scale = 1.0f;


for(int z = 0; z &lt; 5 - 1; z++)
{
for(int x = 0; x &lt; 5 - 1; x++)
{
glBegin(GL_QUADS);
glVertex3f(x * scale, heightmap[z][x], z * scale);
glVertex3f((x + 1) * scale, heightmap[z][x + 1], z * scale);
glVertex3f((x + 1) * scale, heightmap[z + 1][x + 1], (z + 1) * scale);
glVertex3f(x * scale, heightmap[z + 1][x], (z + 1) * scale);
glEnd();
}
}



thanks in advance.

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OK, without knowing the other code I'd guess the problem lies with your camera.

If you don't set up a camera matrix, the default camera position is at (0,0,0) looking along the z-axis. You translated the quads already but only on z, so basically you'd see your heightmap like -----. Try some different height values for a quick test, translate on y a well or use a different camera position and rotation.

A small side note:

Move the glBegin() and glEnd() calls out of the loop:

glBegin(...);
loop goes here
glEnd();

This will get you better performance.

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Try

gluLookAt(0, 5, 0, //position of camera
2, 0, -3, //lookat point (center of your terrain)
0, 1, 0); //up vector for camera


Also try disabling backface culling [ glDisable(GL_CULL_FACE) ] to make sure the quads will always be drawn.

Ah, and a very important note: don't use quads for heightmaps! In your basic case they might work (all heights are 0) but if heights are different you might end up with bent quads. Those might be accepted by your driver but if so you can't be sure of how they are rendered (normally the driver would split them into triangles, however which diagonal is used as split axis is uncertain).

So change your render code to use 2 triangles instead of 1 quad.

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not to be a pest :O but still nothing. Used gluLookAt and disabled cull-face in my initgl.

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I'd say we need a bit more of your code then.

Did you use triangles instead of quads?

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alright, here's all my code.


#include <windows.h> // Header File For Windows
#include <gl\gl.h> // Header File For The OpenGL32 Library
#include <gl\glu.h> // Header File For The GLu32 Library
#include <gl\glaux.h> // Header File For The Glaux Library

HDC hDC=NULL; // Private GDI Device Context
HGLRC hRC=NULL; // Permanent Rendering Context
HWND hWnd=NULL; // Holds Our Window Handle
HINSTANCE hInstance; // Holds The Instance Of The Application

bool keys[256]; // Array Used For The Keyboard Routine
bool active=TRUE; // Window Active Flag Set To TRUE By Default
bool fullscreen=TRUE; // Fullscreen Flag Set To Fullscreen Mode By Default
float heightmap[5][5] =
{{ '0', '0', '0', '0', '0' },
{ '0', '0', '0', '0', '0' },
{ '0', '0', '0', '0', '0' },
{ '0', '0', '0', '0', '0' },
{ '0', '0', '0', '0', '0' }};
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM); // Declaration For WndProc

GLvoid ReSizeGLScene(GLsizei width, GLsizei height) // Resize And Initialize The GL Window
{
if (height==0) // Prevent A Divide By Zero By
{
height=1; // Making Height Equal One
}

glViewport(0,0,width,height); // Reset The Current Viewport

glMatrixMode(GL_PROJECTION); // Select The Projection Matrix
glLoadIdentity(); // Reset The Projection Matrix

// Calculate The Aspect Ratio Of The Window
gluPerspective(45.0f,(GLfloat)width/(GLfloat)height,0.1f,100.0f);

glMatrixMode(GL_MODELVIEW); // Select The Modelview Matrix
glLoadIdentity(); // Reset The Modelview Matrix
}

int InitGL(GLvoid) // All Setup For OpenGL Goes Here
{
glShadeModel(GL_SMOOTH); // Enable Smooth Shading
glClearColor(0.0f, 0.0f, 0.0f, 0.5f); // Black Background
glClearDepth(1.0f); // 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
glDisable(GL_CULL_FACE);
return TRUE; // Initialization Went OK
}

int DrawGLScene(GLvoid) // Here's Where We Do All The Drawing
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Clear Screen And Depth Buffer
glLoadIdentity(); // Reset The Current Modelview Matrix
glTranslatef(0.0f,0.0f,-5.0f);
glColor3f(0.0f,1.0f,0.1f);
gluLookAt(0, 5, 0, //position of camera
2, 0, -3, //lookat point (center of your terrain)
0, 1, 0); //up vector for camera
float scale = 1.0f;


for(int z = 0; z < 5 - 1; z++)
{
for(int x = 0; x < 5 - 1; x++)
{
glBegin(GL_QUADS);
glVertex3f(x * scale, heightmap[z][x], z * scale);
glVertex3f((x + 1) * scale, heightmap[z][x + 1], z * scale);
glVertex3f((x + 1) * scale, heightmap[z + 1][x + 1], (z + 1) * scale);
glVertex3f(x * scale, heightmap[z + 1][x], (z + 1) * scale);
glEnd();
}
}

return TRUE; // Keep Going
}

GLvoid KillGLWindow(GLvoid) // Properly Kill The Window
{
if (fullscreen) // Are We In Fullscreen Mode?
{
ChangeDisplaySettings(NULL,0); // If So Switch Back To The Desktop
ShowCursor(TRUE); // Show Mouse Pointer
}

if (hRC) // Do We Have A Rendering Context?
{
if (!wglMakeCurrent(NULL,NULL)) // Are We Able To Release The DC And RC Contexts?
{
MessageBox(NULL,"Release Of DC And RC Failed.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
}

if (!wglDeleteContext(hRC)) // Are We Able To Delete The RC?
{
MessageBox(NULL,"Release Rendering Context Failed.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
}
hRC=NULL; // Set RC To NULL
}

if (hDC && !ReleaseDC(hWnd,hDC)) // Are We Able To Release The DC
{
MessageBox(NULL,"Release Device Context Failed.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
hDC=NULL; // Set DC To NULL
}

if (hWnd && !DestroyWindow(hWnd)) // Are We Able To Destroy The Window?
{
MessageBox(NULL,"Could Not Release hWnd.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
hWnd=NULL; // Set hWnd To NULL
}

if (!UnregisterClass("OpenGL",hInstance)) // Are We Able To Unregister Class
{
MessageBox(NULL,"Could Not Unregister Class.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
hInstance=NULL; // Set hInstance To NULL
}
}

/* This Code Creates Our OpenGL Window. Parameters Are: *
* title - Title To Appear At The Top Of The Window *
* width - Width Of The GL Window Or Fullscreen Mode *
* height - Height Of The GL Window Or Fullscreen Mode *
* bits - Number Of Bits To Use For Color (8/16/24/32) *
* fullscreenflag - Use Fullscreen Mode (TRUE) Or Windowed Mode (FALSE) */


BOOL CreateGLWindow(char* title, int width, int height, int bits, bool fullscreenflag)
{
GLuint PixelFormat; // Holds The Results After Searching For A Match
WNDCLASS wc; // Windows Class Structure
DWORD dwExStyle; // Window Extended Style
DWORD dwStyle; // Window Style
RECT WindowRect; // Grabs Rectangle Upper Left / Lower Right Values
WindowRect.left=(long)0; // Set Left Value To 0
WindowRect.right=(long)width; // Set Right Value To Requested Width
WindowRect.top=(long)0; // Set Top Value To 0
WindowRect.bottom=(long)height; // Set Bottom Value To Requested Height

fullscreen=fullscreenflag; // Set The Global Fullscreen Flag

hInstance = GetModuleHandle(NULL); // Grab An Instance For Our Window
wc.style = CS_HREDRAW | CS_VREDRAW | CS_OWNDC; // Redraw On Size, And Own DC For Window.
wc.lpfnWndProc = (WNDPROC) WndProc; // WndProc Handles Messages
wc.cbClsExtra = 0; // No Extra Window Data
wc.cbWndExtra = 0; // No Extra Window Data
wc.hInstance = hInstance; // Set The Instance
wc.hIcon = LoadIcon(NULL, IDI_WINLOGO); // Load The Default Icon
wc.hCursor = LoadCursor(NULL, IDC_ARROW); // Load The Arrow Pointer
wc.hbrBackground = NULL; // No Background Required For GL
wc.lpszMenuName = NULL; // We Don't Want A Menu
wc.lpszClassName = "OpenGL"; // Set The Class Name

if (!RegisterClass(&wc)) // Attempt To Register The Window Class
{
MessageBox(NULL,"Failed To Register The Window Class.","ERROR",MB_OK|MB_ICONEXCLAMATION);
return FALSE; // Return FALSE
}

if (fullscreen) // Attempt Fullscreen Mode?
{
DEVMODE dmScreenSettings; // Device Mode
memset(&dmScreenSettings,0,sizeof(dmScreenSettings)); // Makes Sure Memory's Cleared
dmScreenSettings.dmSize=sizeof(dmScreenSettings); // Size Of The Devmode Structure
dmScreenSettings.dmPelsWidth = width; // Selected Screen Width
dmScreenSettings.dmPelsHeight = height; // Selected Screen Height
dmScreenSettings.dmBitsPerPel = bits; // Selected Bits Per Pixel
dmScreenSettings.dmFields=DM_BITSPERPEL|DM_PELSWIDTH|DM_PELSHEIGHT;

// Try To Set Selected Mode And Get Results. NOTE: CDS_FULLSCREEN Gets Rid Of Start Bar.
if (ChangeDisplaySettings(&dmScreenSettings,CDS_FULLSCREEN)!=DISP_CHANGE_SUCCESSFUL)
{
// If The Mode Fails, Offer Two Options. Quit Or Use Windowed Mode.
if (MessageBox(NULL,"The Requested Fullscreen Mode Is Not Supported By\nYour Video Card. Use Windowed Mode Instead?","NeHe GL",MB_YESNO|MB_ICONEXCLAMATION)==IDYES)
{
fullscreen=FALSE; // Windowed Mode Selected. Fullscreen = FALSE
}
else
{
// Pop Up A Message Box Letting User Know The Program Is Closing.
MessageBox(NULL,"Program Will Now Close.","ERROR",MB_OK|MB_ICONSTOP);
return FALSE; // Return FALSE
}
}
}

if (fullscreen) // Are We Still In Fullscreen Mode?
{
dwExStyle=WS_EX_APPWINDOW; // Window Extended Style
dwStyle=WS_POPUP; // Windows Style
ShowCursor(FALSE); // Hide Mouse Pointer
}
else
{
dwExStyle=WS_EX_APPWINDOW | WS_EX_WINDOWEDGE; // Window Extended Style
dwStyle=WS_OVERLAPPEDWINDOW; // Windows Style
}

AdjustWindowRectEx(&WindowRect, dwStyle, FALSE, dwExStyle); // Adjust Window To True Requested Size

// Create The Window
if (!(hWnd=CreateWindowEx( dwExStyle, // Extended Style For The Window
"OpenGL", // Class Name
title, // Window Title
dwStyle | // Defined Window Style
WS_CLIPSIBLINGS | // Required Window Style
WS_CLIPCHILDREN, // Required Window Style
0, 0, // Window Position
WindowRect.right-WindowRect.left, // Calculate Window Width
WindowRect.bottom-WindowRect.top, // Calculate Window Height
NULL, // No Parent Window
NULL, // No Menu
hInstance, // Instance
NULL))) // Dont Pass Anything To WM_CREATE
{
KillGLWindow(); // Reset The Display
MessageBox(NULL,"Window Creation Error.","ERROR",MB_OK|MB_ICONEXCLAMATION);
return FALSE; // Return FALSE
}

static PIXELFORMATDESCRIPTOR pfd= // pfd Tells Windows How We Want Things To Be
{
sizeof(PIXELFORMATDESCRIPTOR), // Size Of This Pixel Format Descriptor
1, // Version Number
PFD_DRAW_TO_WINDOW | // Format Must Support Window
PFD_SUPPORT_OPENGL | // Format Must Support OpenGL
PFD_DOUBLEBUFFER, // Must Support Double Buffering
PFD_TYPE_RGBA, // Request An RGBA Format
bits, // Select Our Color Depth
0, 0, 0, 0, 0, 0, // Color Bits Ignored
0, // No Alpha Buffer
0, // Shift Bit Ignored
0, // No Accumulation Buffer
0, 0, 0, 0, // Accumulation Bits Ignored
16, // 16Bit Z-Buffer (Depth Buffer)
0, // No Stencil Buffer
0, // No Auxiliary Buffer
PFD_MAIN_PLANE, // Main Drawing Layer
0, // Reserved
0, 0, 0 // Layer Masks Ignored
};

if (!(hDC=GetDC(hWnd))) // Did We Get A Device Context?
{
KillGLWindow(); // Reset The Display
MessageBox(NULL,"Can't Create A GL Device Context.","ERROR",MB_OK|MB_ICONEXCLAMATION);
return FALSE; // Return FALSE
}

if (!(PixelFormat=ChoosePixelFormat(hDC,&pfd))) // Did Windows Find A Matching Pixel Format?
{
KillGLWindow(); // Reset The Display
MessageBox(NULL,"Can't Find A Suitable PixelFormat.","ERROR",MB_OK|MB_ICONEXCLAMATION);
return FALSE; // Return FALSE
}

if(!SetPixelFormat(hDC,PixelFormat,&pfd)) // Are We Able To Set The Pixel Format?
{
KillGLWindow(); // Reset The Display
MessageBox(NULL,"Can't Set The PixelFormat.","ERROR",MB_OK|MB_ICONEXCLAMATION);
return FALSE; // Return FALSE
}

if (!(hRC=wglCreateContext(hDC))) // Are We Able To Get A Rendering Context?
{
KillGLWindow(); // Reset The Display
MessageBox(NULL,"Can't Create A GL Rendering Context.","ERROR",MB_OK|MB_ICONEXCLAMATION);
return FALSE; // Return FALSE
}

if(!wglMakeCurrent(hDC,hRC)) // Try To Activate The Rendering Context
{
KillGLWindow(); // Reset The Display
MessageBox(NULL,"Can't Activate The GL Rendering Context.","ERROR",MB_OK|MB_ICONEXCLAMATION);
return FALSE; // Return FALSE
}

ShowWindow(hWnd,SW_SHOW); // Show The Window
SetForegroundWindow(hWnd); // Slightly Higher Priority
SetFocus(hWnd); // Sets Keyboard Focus To The Window
ReSizeGLScene(width, height); // Set Up Our Perspective GL Screen

if (!InitGL()) // Initialize Our Newly Created GL Window
{
KillGLWindow(); // Reset The Display
MessageBox(NULL,"Initialization Failed.","ERROR",MB_OK|MB_ICONEXCLAMATION);
return FALSE; // Return FALSE
}

return TRUE; // Success
}

LRESULT CALLBACK WndProc( HWND hWnd, // Handle For This Window
UINT uMsg, // Message For This Window
WPARAM wParam, // Additional Message Information
LPARAM lParam) // Additional Message Information
{
switch (uMsg) // Check For Windows Messages
{
case WM_ACTIVATE: // Watch For Window Activate Message
{
if (!HIWORD(wParam)) // Check Minimization State
{
active=TRUE; // Program Is Active
}
else
{
active=FALSE; // Program Is No Longer Active
}

return 0; // Return To The Message Loop
}

case WM_SYSCOMMAND:
{
switch (wParam)
{
case SC_SCREENSAVE:
case SC_MONITORPOWER:
return 0;
}
break;
}

case WM_CLOSE: // Did We Receive A Close Message?
{
PostQuitMessage(0); // Send A Quit Message
return 0; // Jump Back
}

case WM_KEYDOWN: // Is A Key Being Held Down?
{
keys[wParam] = TRUE; // If So, Mark It As TRUE
return 0; // Jump Back
}

case WM_KEYUP: // Has A Key Been Released?
{
keys[wParam] = FALSE; // If So, Mark It As FALSE
return 0; // Jump Back
}

case WM_SIZE: // Resize The OpenGL Window
{
ReSizeGLScene(LOWORD(lParam),HIWORD(lParam)); // LoWord=Width, HiWord=Height
return 0; // Jump Back
}
}

// Pass All Unhandled Messages To DefWindowProc
return DefWindowProc(hWnd,uMsg,wParam,lParam);
}

int WINAPI WinMain( HINSTANCE hInstance, // Instance
HINSTANCE hPrevInstance, // Previous Instance
LPSTR lpCmdLine, // Command Line Parameters
int nCmdShow) // Window Show State
{
MSG msg; // Windows Message Structure
BOOL done=FALSE; // Bool Variable To Exit Loop

// Ask The User Which Screen Mode They Prefer
if (MessageBox(NULL,"Would You Like To Run In Fullscreen Mode?", "Start FullScreen?",MB_YESNO|MB_ICONQUESTION)==IDNO)
{
fullscreen=FALSE; // Windowed Mode
}

// Create Our OpenGL Window
if (!CreateGLWindow("Plasma Algorithm",640,480,16,fullscreen))
{
return 0; // Quit If Window Was Not Created
}

while(!done) // Loop That Runs While done=FALSE
{
if (PeekMessage(&msg,NULL,0,0,PM_REMOVE)) // Is There A Message Waiting?
{
if (msg.message==WM_QUIT) // Have We Received A Quit Message?
{
done=TRUE; // If So done=TRUE
}
else // If Not, Deal With Window Messages
{
TranslateMessage(&msg); // Translate The Message
DispatchMessage(&msg); // Dispatch The Message
}
}
else // If There Are No Messages
{
// Draw The Scene. Watch For ESC Key And Quit Messages From DrawGLScene()
if ((active && !DrawGLScene()) || keys[VK_ESCAPE]) // Active? Was There A Quit Received?
{
done=TRUE; // ESC or DrawGLScene Signalled A Quit
}
else // Not Time To Quit, Update Screen
{
SwapBuffers(hDC); // Swap Buffers (Double Buffering)
}

if (keys[VK_F1]) // Is F1 Being Pressed?
{
keys[VK_F1]=FALSE; // If So Make Key FALSE
KillGLWindow(); // Kill Our Current Window
fullscreen=!fullscreen; // Toggle Fullscreen / Windowed Mode
// Recreate Our OpenGL Window
if (!CreateGLWindow("Colored Polygon Tutorial",640,480,16,fullscreen))
{
return 0; // Quit If Window Was Not Created
}
}
}
}

// Shutdown
KillGLWindow(); // Kill The Window
return (msg.wParam); // Exit The Program
}

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Well, erm ..., ok, I built your code and tried it.

You know what? The error was in the first bit of code you posted, but I didn't see it [cry].

So here it is:

You defined your array as

float heightmap[5][5] = {{ '0', '0','0','0','0'} ...

'0' is defined as int = 48 (and this is converted to float = 48.0f) since it is a character! So your array was not 0, 0, 0 , ... but 48, 48, 48, ...

Replace '0' with just 0 and it should work!

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woot, thanks. Now I have my rendering done, just gotta get the heightmap itself to generate. Thanks.

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