Ok, so I'm trying to get this shader to load 4 textures and blend them together (for tiling reasons).

#version 330

in vec2 TexCoord0;

uniform sampler2D gTex0;
uniform sampler2D gTex1;
uniform sampler2D gTex2;
uniform sampler2D gTex3;

out vec4 FragColor;

void main()
{
    vec4 color1 = texture2D(gTex0, TexCoord0);
    vec4 color2 = texture2D(gTex1, TexCoord0);
    vec4 color3 = texture2D(gTex2, TexCoord0);
    vec4 color4 = texture2D(gTex3, TexCoord0);

    color1 = color1 * (1 - TexCoord0.x) * TexCoord0.y;
    color2 = color2 * (1 - TexCoord0.x) * (1 - TexCoord0.y);
    color3 = color3 * TexCoord0.x * (1 - TexCoord0.y);
    color4 = color4 * TexCoord0.x * TexCoord0.y;

    FragColor = color1 + color2 + color3 + color4;
}

If i do 'FragColor = color1' (or any of the colors, like FragColor = color3 etc) it draws the texture, fading from its full color to black as it should do. Each of these textures work on their own, but when trying to use 2 or more (such as "FragColor = color1 + color2;"), it just renders black for some reason.

I can switch the color1/color2/color3/color4 in the shader without touching any other code and it renders that texture, so im guessing that it is loading in all of the textures correctly.

If you need to see more code let me know, but it feels like the error is within the fragment shader itself.

Thanks

Is there, by any chance, texture coords in vertices bigger than 1.0?

Thanks for your responses.

No I manually input the data:

m_tileMesh = new MESH[m_numOfTiles];
	VERTEX Vertices[4];

	for (int x = 0; x < m_width; x++)
	for (int z = 0; z < m_height; z++)
	{
// VECTOR2f is the texture coordinate
		Vertices[0] = VERTEX(VECTOR3f(x + 0.5f, z + 0.5f, 10.0f), VECTOR2f(0.0f, 0.0f), VECTOR3f());
		Vertices[1] = VERTEX(VECTOR3f(x + 0.5f, z + -0.5f, 10.0f), VECTOR2f(1.0f, 0.0f), VECTOR3f());
		Vertices[2] = VERTEX(VECTOR3f(x + -0.5f, z + -0.5f, 10.0f), VECTOR2f(1.0f, 1.0f), VECTOR3f());
		Vertices[3] = VERTEX(VECTOR3f(x + -0.5f, z + 0.5f, 10.0f), VECTOR2f(0.0f, 1.0f), VECTOR3f());

		uint Indices[] = { 0, 1, 2, 0, 2, 3 };

		m_tileMesh[z + x * m_width].LoadNewMesh(Vertices, 4, Indices, 6);
	}

I must say again that using just ONE of the textures works just fine, that being any of them, but using 2 or more at once makes it bug out.

I'm trying to make an rts game, and as such the tiles need to blend. Each corner of every tile is a seperate texture, so I'm needing to blend 4 textures together (or 3 really since it's 2trangles for each quad, but im not optimizing yet, just trying to get it working).

Ok here we go:

void MAP::DrawMap()
{
	// Makes this shader the current shader
	m_shader->Bind();
	
	// m_shader->GetProgramID() get's the ID of the shader.
	glUniform1i(glGetUniformLocation(m_shader->GetProgramID(), "gTex0"), GL_TEXTURE0);
	glUniform1i(glGetUniformLocation(m_shader->GetProgramID(), "gTex1"), GL_TEXTURE1);
	glUniform1i(glGetUniformLocation(m_shader->GetProgramID(), "gTex2"), GL_TEXTURE2);
	glUniform1i(glGetUniformLocation(m_shader->GetProgramID(), "gTex3"), GL_TEXTURE3);

	for (int x = 0; x < m_width; x++)
	for (int z = 0; z < m_height; z++)
	{
		glActiveTexture(GL_TEXTURE0);
		glBindTexture(GL_TEXTURE_2D, m_tilePoint[m_tile[x * m_width + z].m_tilePoint[0]].m_texID);

		glActiveTexture(GL_TEXTURE1);
		glBindTexture(GL_TEXTURE_2D, m_tilePoint[m_tile[x * m_width + z].m_tilePoint[1]].m_texID);

		glActiveTexture(GL_TEXTURE2);
		glBindTexture(GL_TEXTURE_2D, m_tilePoint[m_tile[x * m_width + z].m_tilePoint[2]].m_texID);

		glActiveTexture(GL_TEXTURE3);
		glBindTexture(GL_TEXTURE_2D, m_tilePoint[m_tile[x * m_width + z].m_tilePoint[3]].m_texID);

		m_tileMesh[z + x * m_width].Render();	// Draws the tile
	}
}

I try to keep my posts as short as I can.

Also just for reference, here it is rendering ONE of the colors in the shader for the tiles (behind the cubes):

So changing which single texture to make the fragcolor would make it pick the texture in one of the other corners, and they fade out just like this.

Any help is greatly appreciated, or if you know an easier way to blend 4 textures together for my purposes, I would also appreciate your input.

Thanks

Edit: changed the background color to blue, doing "FragColor = color1 + color2;" instead of "FragColor = colorx;" //x being any color, and when adding two colors, it doesn't render anything at all. as in I just see blue background, no black squares.

Pretty sure this:
glUniform1i(glGetUniformLocation(m_shader->GetProgramID(), "gTex0"), GL_TEXTURE0);
has to be
glUniform1i(glGetUniformLocation(m_shader->GetProgramID(), "gTex0"), 0);

Wow man, wow. Ok that worked, I'm so stupid.

Maybe I should read up on these opengl functions a little more.

Thanks so much man, you rock! it looks beautiful

EDIT: Results

nevermind - disregard this post ;)