GL error GL_INVALID_OPERATION: mismatched type setting uniform of location "4" in program "1"

Question

I get this error while trying to add lighting

Message: Error has been generated. GL error GL_INVALID_OPERATION in Uniform1i: (ID: 2882512024) GL error GL_INVALID_OPERATION: mismatched type setting uniform of location "4" in program 1, "" using shaders, 2, "", 3, ""
type: ERROR --- id: 1282 --- severity: HIGH

this is my fragmentshader

out vec4 color;

in VS_OUT
{
    vec2 tc;
    vec3 normals;
} 

fs_in;


layout(binding=0)uniform sampler2D tex; 

uniform vec3 lightColor;

void main(void)
{
color= texture(tex, fs_in.tc)* vec4(lightColor, 1.0);

}

I have this in my render

GLint lightColor_location = glGetUniformLocation(program, "lightColor");
    glUniform1i(lightColor_location, 0);
    glUniform3f(lightColor_location, lightColor.r, lightColor.g, lightColor.b);

and this declared

glm::vec3 lightColor = glm::vec3(1.0f, 1.0f, 1.0f);
```

Answer 1

glUniform1i(lightColor_location, 0);

This says "set lightColor to the single number value zero".

But lightColor isn't a single number - it's three numbers! You can't set a variable that wants three numbers by giving it only one.

The line immediately after that looks more correct:

glUniform3f(lightColor_location, lightColor.r, lightColor.g, lightColor.b);

Here we're trying to set a 3-component variable by giving it 3 numbers, so we've matched the input to the intended output.