History: Peter's Grid System

Introduction

After some digging around about grid systems and trying Jeroen Dierckx's EditorGridSystem, We decided to write our own grid system with different feature set and release it to the community, because Ogre is si cool.

Screenshots

Features

Following features are supported by Peter's Grid System:

• This grid have three planes support - XY, XZ, YZ that can be visible/hidden
• Grid is generated/updated by request, uses ManualObject
• Limitations in each dimension
• Cell size per dimension
• Grid Offset
• Colors for offset, master and division axis,
• Does NOT depend from the camera type used,
• Not limited to one instance (no named items used!)

Usage

To create a grid, just create an instance of the class and set the properties you want to, then call update()

/*OgreGrid*/ grid = new OgreGrid(/*Ogre::SceneManager*/ui->TheScene->scene, /*Material name*/"BaseWhiteAlphaBlended");

    //Where to draw the grid?
    grid->drawQueue = Ogre::RENDER_QUEUE_OVERLAY;

    //Attach it to some SceneNode
    grid->attachToNode(scene->getRootSceneNode());

    //Some grid settings
    grid->setCellSize(0.5);
    grid->ymin = -9;
    grid->ymax = 2;
    grid->ofY = 2;
    grid->zmin = -2;
    grid->zmax = 1;
    grid->showXZ = true;
    grid->showXY = true;
    grid->showYZ = true;
    grid->setDivisions(10);
    grid->colorDivision = Ogre::ColourValue(0,1,0,0.3);
    grid->colorOffset = Ogre::ColourValue(0,0,1,1);
    grid->colorMaster = Ogre::ColourValue(1,0,0,0.7);

    //Regenerate the grid
    grid->update();

Options

After creating an instance to the grid class, you can set the options of the grid you want to. After you change option, you must call update() to update the grid manually. All options are public data members with the exception of some convenience setters.

Cell sizes:

float csX, csY, csZ are used to control the master grid axes distance, per dimaneion. You may have a grid with cell size 2x1 in the X/Y dimension. You can use grid sizes such as 0.5x0.5. You can also use setCellSize(float size) and setCellSize(float x, float y, float z) for this purpose.

Zero offset:

float ofX, ofY, ofZ are used to move the center of the grid in each dimension. You can also use setOffset(float x, float y, float z)

Division count:

int divX, divY, divZ are used to set the number of subdivisions in each dimension. You can also use setDivisions(int n) and setDivisions(int x,int y,int z) for this purpose. To show or hide the divisions and use only the master axes, set bool showDivisions

Grid range limitations:

Our grid is limited to certain values in each division. If axis is limited from -5 to +5, only these cells that are in this range will be drawn for the given dimension. Limitations are set via int xmin, xmax, ymin, ymax, zmin, zmax. Note that the default limitations are from -5 to +5, and the system does not support infinite grids still. In the future, I may decide to implement infinite planes. Also, setting huge limitations will generate too much lines and may affect performance, especially if there are too much divisions, as well.

Shown planes:

You can set which grid plane is drawn by setting bool showXY, showXZ, showYZ as you like. By default, only the XY plane is shown.

Colors:

• colorMaster - The color of master lines. Master lines are drawn each cell size units.
• colorOffset - The color of the offset lines, e.g. these that pass thru (0,0,0)+Grid's offset
• colorDivision - The color of the division lines. You usually want to set lighter color for these.

Please note that the default material, "BaseWhiteNoLighting", does not support alpha from the vertex colors. Peter's Grid System uses vertex colors for grid lines color, and all this is within 1 section in 1 ManualObject. If you want alpha, you can use the following material:

material "BaseWhiteAlphaBlended"
{
	receive_shadows on
	transparency_casts_shadows off
	technique
	{
		lod_index 0
		scheme Default
		pass
		{
			lighting off
			max_lights 8
			start_light 0
			iteration once
			point_size 4
			point_sprites off
			point_size_attenuation off
			point_size_min 0
			point_size_max 0
			scene_blend alpha_blend
			depth_check on
			alpha_rejection always_pass 0
			alpha_to_coverage off
			transparent_sorting on
			depth_write on
			depth_func less_equal
			depth_bias 0 0
			iteration_depth_bias 0
			light_scissor off
			light_clip_planes off
			cull_hardware clockwise
			cull_software back
			shading gouraud
			polygon_mode solid
			polygon_mode_overrideable on
			normalise_normals off
			fog_override false
		}
	}
}