Jump to content
  • Advertisement
Sign in to follow this  
xtheendx

Rotating Meshes Independently

This topic is 3028 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

Hey guys I am trying to render three teapot and get them to rotate them independently, but once I get three on the screen using D3DXMatrixTranslation the rotation stops. Only way I can get it to rotate is to just draw one. Why is this? Can it be done in shader code?
void render_frame(void)
{
    d3ddev->Clear(0, NULL, D3DCLEAR_TARGET, D3DCOLOR_XRGB(0, 0, 0), 1.0f, 0);
    d3ddev->Clear(0, NULL, D3DCLEAR_ZBUFFER, D3DCOLOR_XRGB(0, 0, 0), 1.0f, 0);

    d3ddev->BeginScene();

    // set the view transform
    D3DXMATRIX matView;    // the view transform matrix
    D3DXMatrixLookAtLH(&matView,
    &D3DXVECTOR3 (0.0f, 3.0f, 9.0f),    // the camera position
    &D3DXVECTOR3 (0.0f, 0.0f, 0.0f),    // the look-at position
    &D3DXVECTOR3 (0.0f, 1.0f, 0.0f));    // the up direction
    effect->SetMatrix("View", &matView);

    // set the projection transform
    D3DXMATRIX matProjection;    // the projection transform matrix
    D3DXMatrixPerspectiveFovLH(&matProjection,
                               D3DXToRadian(45),    // the horizontal field of view
                               (FLOAT)SCREEN_WIDTH / (FLOAT)SCREEN_HEIGHT, // aspect ratio
                               1.0f,    // the near view-plane
                               100.0f);    // the far view-plane

    effect->SetMatrix("Projection", &matProjection);

	// set the world transform
    static float index = 0.0f; index+=0.03f;    // an ever-increasing float value
    D3DXMATRIX matRotateY;    // a matrix to store the rotation for each triangle
    D3DXMatrixRotationY(&matRotateY, index);    // the rotation matrix
	effect->SetMatrix("World", &matRotateY);

	for(int count = 0; count < 3; count++)
    {
		static D3DXMATRIX matCopy;
        D3DXMatrixTranslation(&matCopy, -3.0f + (3*count), 0.0f, 0.0f);
        effect->SetMatrix("World", &matCopy);

		effect->Begin(NULL, NULL);    // begin using the effect
			effect->BeginPass(0);    // begin the pass

				// render whatever
				meshTeapot->DrawSubset(0);

			effect->EndPass();    // end the pass
		effect->End();    // end the effect
	}
    d3ddev->EndScene(); 

    d3ddev->Present(NULL, NULL, NULL, NULL);

    return;
}

simple vertex shader I am using.
float4x4 World;
float4x4 View;
float4x4 Projection;

struct VertexOut
{
    float4 Pos : POSITION;
    float4 Color : COLOR;
};

VertexOut VShader(float4 Pos : POSITION)
{
    VertexOut Vert = (VertexOut)0;
    float4x4 Transform;

    Transform = mul(World, View);
    Transform = mul(Transform, Projection);
    Vert.Pos = mul(Pos, Transform);

    Vert.Color = float4(1, 1, 1, 1);

    return Vert;
}

technique FirstTechnique
{
    pass FirstPass
    {
        Lighting = FALSE;
        ZEnable = TRUE;

        VertexShader = compile vs_2_0 VShader();
    }
}

Share this post


Link to post
Share on other sites
Advertisement
If you want to combine a rotation and a translation, then you need to concatenate the matrices (AKA multiply them). Try this:


static float index = 0.0f; index+=0.03f; // an ever-increasing float value
D3DXMATRIX matRotateY; // a matrix to store the rotation for each triangle
D3DXMatrixRotationY(&matRotateY, index); // the rotation matrix

for(int count = 0; count < 3; count++)
{
D3DXMATRIX matCopy;
D3DXMatrixTranslation(&matCopy, -3.0f + (3*count), 0.0f, 0.0f);
matCopy = matRotateY * matCopy;
effect->SetMatrix("World", &matCopy);

...
}

Share this post


Link to post
Share on other sites
That worked like a charm and makes sense. I have trying to do them seperlatly but combining them makes alot more sense. Thank you!

Share this post


Link to post
Share on other sites
Sign in to follow this  

  • Advertisement
×

Important Information

By using GameDev.net, you agree to our community Guidelines, Terms of Use, and Privacy Policy.

Participate in the game development conversation and more when you create an account on GameDev.net!

Sign me up!