Simple Shader Question

Troubleshooting graphics
1

Am I completely off base here, or shouldn’t I be able to move a texture (basing this off of the Unshaded material/vert/frag) by updating texCoord1?



If I slowly increase the x or y of the vec2 from 0 to 1, shouldn’t it move the texture?



Reaaaaallly sorry for the stupid question.

2

Yes, it should. But if it isn’t then we haven’t been given enough information as to why it isn’t.

3

So, I updated the Unshaded.vert with the following (material def file allows for setting Offset)



[java]

uniform mat4 g_WorldViewProjectionMatrix;

attribute vec3 inPosition;



#if defined(HAS_COLORMAP) || (defined(HAS_LIGHTMAP) && !defined(SEPARATE_TEXCOORD))

#define NEED_TEXCOORD1

#endif



#ifdef NEED_TEXCOORD1

attribute vec2 inTexCoord;

varying vec2 texCoord1;

varying vec2 Offset;

#endif



#ifdef SEPARATE_TEXCOORD

attribute vec2 inTexCoord2;

varying vec2 texCoord2;

#endif



#ifdef HAS_VERTEXCOLOR

attribute vec4 inColor;

varying vec4 vertColor;

#endif



void main(){

#ifdef NEED_TEXCOORD1

texCoord1 = vec2((inTexCoord[0]+Offset[0]),(inTexCoord[1]+Offset[1]));

#endif



#ifdef SEPARATE_TEXCOORD

texCoord2 = inTexCoord2;

#endif



#ifdef HAS_VERTEXCOLOR

vertColor = inColor;

#endif



gl_Position = g_WorldViewProjectionMatrix * vec4(inPosition, 1.0);

}

[/java]





So the loop updates Offset from value 0 to 1 in increments of .01f

The texture moves… only when I rotate the camera along the Zaxis (looking up and down). I know it has something to do with the last line (gl_Position). I am assuming I need to swap out WorldView for something Local to the rendered object?



Any help would be appreciated!

4

Offset is not a uniform it’s a varying… so it probably contains random garbage that changes as you look around.



I’m surprised it compiled at all.



Did you want it to be a uniform or a vertex attribute?



Also note that you can just use g_Time if you set that up right in the j3md.

1 Like
5

I see now. Let me try setting it to a uniform.

6

Also, if you have a uniform named “Offset” then it will be “m_Offset” in the shaders.

1 Like
7

This worked like a charm!



[java]

uniform mat4 g_WorldViewProjectionMatrix;

attribute vec3 inPosition;



#if defined(HAS_COLORMAP) || (defined(HAS_LIGHTMAP) && !defined(SEPARATE_TEXCOORD))

#define NEED_TEXCOORD1

#endif



#ifdef NEED_TEXCOORD1

attribute vec2 inTexCoord;

varying vec2 texCoord1;

uniform vec2 m_Offset;

#endif



#ifdef SEPARATE_TEXCOORD

attribute vec2 inTexCoord2;

varying vec2 texCoord2;

#endif



#ifdef HAS_VERTEXCOLOR

attribute vec4 inColor;

varying vec4 vertColor;

#endif



void main(){

#ifdef NEED_TEXCOORD1

texCoord1 = vec2((inTexCoord[0]+m_Offset[0]),(inTexCoord[1]+m_Offset[1]));

#endif



#ifdef SEPARATE_TEXCOORD

texCoord2 = inTexCoord2;

#endif



#ifdef HAS_VERTEXCOLOR

vertColor = inColor;

#endif



gl_Position = g_WorldViewProjectionMatrix * vec4(inPosition, 1.0);

}

[/java]



Now to figure out how to set up the g_Time in the material def file. Although, I would love to be able to vary the speed, so I am assuming I’ll need to define this as well.



Thanks a ton for the help!

8

Yeah, but speed won’t need to be set as often as offset, probably.



Under WorldParameters… put Time



Then you will have access to g_Time in your shader.